Slow/Fast Deceleration causing Sputter/Stall

[jkruem]

I cannot figure out this sputter/stall issue. My truck is a 1997 Ford Ranger 2.3L Manual Transmission with 200,000 miles.

Here are the tests I have done:

1. When I start up the truck and begin DRIVING and come to STOP sign SLOWLY, the engine will begin to SPUTTER at the end of DECELERATION. If I sit at the stop, it will work itself out and run smooth after about 10 seconds. (Only happens during the first 2 minutes of driving then the problem goes away.)

2. When I start up the truck and begin DRIVING and come to a STOP sign QUICKLY, the engine will STALL out at the end of DECELERATION. If I try to start it back up, it won´t turn over until about 10 seconds later. Then it runs kind of rough then smooths out again.(Only happens during the first 2 minutes of driving then the problem goes away.)

3. When I start up the truck and begin DRIVING and push in the CLUTCH and coast then come to a STOP sign QUICKLY, the engine will stall out. If I try to start it back up, it won´t turn over until about 10 seconds later. Then it runs kind of rough then smooths out again.(Only happens during the first 2 minutes of driving then the problem goes away.)

4. When I start up the truck and just let it IDLE IN PLACE it runs smooth, but when I accelerate it, it begins to sputter at the end of the DECELERATION. The HIGHER THE DECELERATION the more likely it will STALL out. Then I wait 10 seconds and start it back up to find it running rough for another 10 seconds and then its smooth again. (This was consistent and did not go away while TESTING this IN NEUTRAL.) (After this test, I drove it around the block and after 2 minutes of driving the symptoms went away back in neutral.)

(Note: Engine is less likely to sputter and stall if I use engine braking by down shifting and using the foot brake just at the very edge of the stop.)

What I have done to try and fix this:

1. Replace Coil Packs, Spark Plugs, and Spark Plug Wires
2. Replace Fuel Filter
3. Replace Fuel Filler Hose (Tank Leak)
4. Replace Throttle Position Sensor
5. Replace Idle Control Valve
6. Replace cracked EVAP hose to Canister
7. Fuel Induction Service completed

CEL code prompts if I decelerate fast enough to have it stall:
Throws a cylinder 4 misfire.

Based on the 4th test above, something about driving seems to help it, while idling in place has no help at all. Does anyone have any idea what this may be caused by? (I am trying to bring this thing back to life, but it is certainly giving me a fight!)

 

[Mark_88]

Sounds like something in the warmup cycle is not working properly. What happens if you start and run till warmup and then shut it off again right away? Does it start right up and run fine or do you have the same situation where it will stall when coming to a stop or deceleration?

Did you recently change or have problems with the thermostat or the temp gauge indicating too cold or lowered engine temperatures?

Reason I'm asking is the warm up cycle in these engines relies on the temperature of the engine to determine how much fuel/air to use. The computer uses feedback from the temperature sensor to help regulate these and if the reading is incorrect the engine will not be getting proper mix of fuel/air to run smoothly.

If you haven't changed the temp sensor (not sender) then it may be causing the issue.

It could be a vacuum leak somewhere too but the fact that it smooths our after warmup means that is unlikely.

These engines have the DPFE system on the exhaust that has two vacuum hoses on them...they may be just loose enough to be causing a small vacuum leak and may just need to be pressed into place...they are on the passenger side near the back of the engine and connect to a box mounted near the back of the engine.

Highest vacuum under lowest RPMs means when you decelerate or at idle a vacuum leak will be more noticeable.

 

[tomw]

There are two sensors in the arena... The Engine Coolant Temperature and Air Charge Temperature, unless they changed the names to protect the innocent.
The first is in contact with the coolant, and informs the ECM of the coolant temperature so the fuel provided can be enriched as cold engines do not atomize the 'normal' amount as well, so the engine is sort of starved and unstable. The ACT tells of ambient air coming in, and informs the computer as the fuel will atomize poorly in cold weather, so same thing.
There may also be a 'stove' mounted to the exhaust manifold that has a metallic tube leading to the air cleaner along with a vacuum operated flap valve to direct heated or ambient air to the intake duct. It has a thermal vacuum valve the releases the flap valve when the incoming air reaches a certain temperature. It helps the fuel atomize by providing heat to the incoming air. Many don't work, FWIW.
One other thing to consider is the IAC - Idle Air Control - it provides air for the engine to run at idle speeds, and modifies the idle rpm and air to match the load, such as A/C compressor and power steering pump. It provides a fast idle when the engine is cold, over 1k rpm. If you don't have a fast idle at cold, the IAC is a likely suspect. They can gum and get sticky, and then don't work as well. It may be possible to clean them and improve their workmanship.
tom

 

[jkruem]

I have an OBDII scanner that I have been using to try and track down the source, however, I do not know where to find a standard set of data to compare what my truck is showing through the scanner. Any thoughts on where to find this information?

@mark_88

If I start it then warm up, then shut it off, then turn it back on and rev the engine it still sputters and wants to stall out at deceleration. (THIS IS IF I STAY IN PLACE AND DO NOT MOVE IT.) *Note: When it sputters it shakes the entire truck too. The higher an RPM I am coming down from at deceleration the harder it shakes my truck and then typically stalls out.*

I have noticed when I stall out as I am coming to a stop, the truck won't kick over till about 10 seconds have passed. If I had to guess, I am thinking somehow it is flooding the engine slightly and it needs the time to back just enough fuel out of the chamber? (The best theory I can come up with so far.)

As for the temperature sensor, I have not checked that out yet. Ill get back to you on this.

(Not sure if this helps, but I noticed that there is what looks like a house extension cord that is fastened to the bottom of my engine somewhere. I am assuming this was used to heat up the oil prior to starting it since it came from somewhere out in the northwest. Wondering if they went through the trouble to use this that they made another type of modification to help heat up the oil? If this is the case, since it is in Atlanta. the climate would be the opposite:
Hot and Humid vs Cold and Dry (Possible?))

@tomw

I replaced the Idle Air Control Valve recently and noted that at a cold startup that it runs a higher rpm till it warms then drops down to around 750rpm. (I think that should check out as working.)

I will check out the other sensors you have mentioned. I haven't looked over these yet.

 

[Mark_88]

OK thanks for the feedback.

You could also check the Fuel Pressure Regulator on the fuel line if you know where it is. There is a vacuum line that runs to that from the intake on the passenger side and if the diaphram is broken it can suck more fuel directly into the pistons and that will flood the engine.

Remove the vacuum hose and smell it for gas. If there is a strong gas smell in the vacuum line then that could be the problem or part of a multiple problem issue.

Your 7th item in the list was fuel induction service completed but did that include a test of the FPR like I just mentioned or did someone else do that for you?

The extension cord could be a block heater like you suspect. If it was factory the block heater may be on the passenger side under the exhaust manifold or some were installed on the driver side under the intake.

I used a block heater on my carbureted engine because cold starting and warmup in winter was brutal without it.

Just on that note check the fluid level in the radiator and reservoir bottle to make sure you have enough in there. Low coolant can cause some really unpleasant side effects like cracked heads and poor performance (fuel not atomized properly).

Other than that...let us know how your testing goes...

 

[tomw]

It seems all your problems go away after two minutes of running. Get thee a time machine, and when you need the truck, set it to two minutes ahead. Problem solved.
OTOH, most of the time machines are imaginary, as in, I am on my way out the door, and somehow 10 minutes evaporates, and I am now likely to be late. Where did the ten minutes go? We all wonder about that.
So, after two minutes your engine should be running in 'closed loop' if the thermostat is working properly.(top radiator hose cold, and then all of a sudden warm->hot real quick)
Before closed loop, it is operating more 'blind', and will use stored table information. The O2 sensor feedback is not taken into account, and the computer spits fuel as it sees fit.
If you have an intake leak, there'll be extra air that the computer will not know to compensate for, and the effect will be even worse when cold, as the engine needs a richer mix of fuel:air because of atomization being less when cold.
I would check the intake, use your smoke machine. (we all have one of those too) If you don't have one, you can use an unlit propane torch and a length of tubing to feed HCx moving the tube, valve open, around the intake. If you find a leak, the engine will run even better. Given it runs w/o miss at idle, that'll be more difficult.
You have a MAF, I believe, and you might try cleaning that, as it informs of airflow, and, if wrong, will mis-inform the computer, which will in turn flow the incorrect amount of fuel. Couldn't hurt.
FWIW, you can make a well running engine go flaky by blipping the throttle multiple times and expecting it to recover smoothly from the quick rpm changes. If you have driving problems, such as stalling regularly when cold at stop signs, etc, that's different. I will say my old truck is 'iffy' in its cold idle. I can make it die w/o any problem at all when cold. Give it some gas, rev it up, start to let out the clutch, and stumble stumble stumble recover or ditto ditto ditto die. Its idle is weak when cold. I live with it, and am about 35 miles from hotlanta, so have somewhat similar weather.
I did find something when I removed the fuel rail & injectors that might have caused the weak idle, but forget what it was momentarily. Durned if it comes to mind right now, but it was something that had been 'wrong' for years, and I fiddled with it, and thought it might help. So far, it has seemed a bit stronger @ cold idle. If/when I remember, I'll post.
tom

 

[JCarr]

Hi Jkruem,

Did you ever find a solution to this problem? My engine is doing the same things when decelerating, and it is sending Cylinder 2 and 4 misfire codes, also had an exhaust gas re-circulation insufficient code a couple weeks ago, but that one hasn't shown again.

My engine will stall out unless I bring it down gently in RPMs myself. But it takes me driving it on the highway for a good 20 minutes to get fully warmed up before it stops stalling at deceleration.

Any thoughts would be greatly appreciated!

Already replaced the coils which were showing out of tolerance, didn't fix.
Spark plugs are 6,000 miles old, look okay
Fuel injectors have been checked, and running fine

I did add seafoam to the engine oil about 140 miles ago, and also did the throttle body spray and hot soak methods, which greatly improved a the rough idling I was having and more cylinder misfires. Just the stalling on deceleration problem is all I have now.

Mechanic said to replace the engine.....but I think they just gave up.

Thinking about taking it to the Ford Dealership next if I can't figure something else out on my own.

Thanks!
Jarrod

 

[Daveo286]

Hi Jkruem,

Did you ever find a solution to this problem? My engine is doing the same things when decelerating, and it is sending Cylinder 2 and 4 misfire codes, also had an exhaust gas re-circulation insufficient code a couple weeks ago, but that one hasn't shown again.

My engine will stall out unless I bring it down gently in RPMs myself. But it takes me driving it on the highway for a good 20 minutes to get fully warmed up before it stops stalling at deceleration.

Any thoughts would be greatly appreciated!

Already replaced the coils which were showing out of tolerance, didn't fix.
Spark plugs are 6,000 miles old, look okay
Fuel injectors have been checked, and running fine

I did add seafoam to the engine oil about 140 miles ago, and also did the throttle body spray and hot soak methods, which greatly improved a the rough idling I was having and more cylinder misfires. Just the stalling on deceleration problem is all I have now.

Mechanic said to replace the engine.....but I think they just gave up.

Thinking about taking it to the Ford Dealership next if I can't figure something else out on my own.

Thanks!
Jarrod

Hi Jkruem,

Did you ever find a solution to this problem? My engine is doing the same things when decelerating, and it is sending Cylinder 2 and 4 misfire codes, also had an exhaust gas re-circulation insufficient code a couple weeks ago, but that one hasn't shown again.

My engine will stall out unless I bring it down gently in RPMs myself. But it takes me driving it on the highway for a good 20 minutes to get fully warmed up before it stops stalling at deceleration.

Any thoughts would be greatly appreciated!

Already replaced the coils which were showing out of tolerance, didn't fix.
Spark plugs are 6,000 miles old, look okay
Fuel injectors have been checked, and running fine

I did add seafoam to the engine oil about 140 miles ago, and also did the throttle body spray and hot soak methods, which greatly improved a the rough idling I was having and more cylinder misfires. Just the stalling on deceleration problem is all I have now.

Mechanic said to replace the engine.....but I think they just gave up.

Thinking about taking it to the Ford Dealership next if I can't figure something else out on my own.

Thanks!
Jarrod

I am wondering the same thing as well! I have found so many threads with this issue and I have changed every part and no luck. I’m guessing no one has figured this out and decided to sell the truck haha but any more info you have on the issue would be appreciated!

 

[Jay11]

Mechanic said to replace the engine.....but I think they just gave up.

Thinking about taking it to the Ford Dealership next if I can't figure something else out on my own

Bad mechanic....hoops you told him to hit the road.

I don't have a solution suggestion for you as an a new ranger owner. I do have the filtering issue so here's my suggestion.....Google engine stalls after changing gear. There's a ton of info on that and may or not be beneficial to you before you have to head to a a stealership Good luck!