97 2.3L Hestitates/Stalls

[runningslow]

I've got a '97 2.3L manual with about ~250k on the clock. The past week or so, the truck has been tripping em up.

On my morning commute with outside temps in the mid 60s, all is well and no problems.

In the afternoon with outside temps in the upper 80s, it'll idle at about 800 rpm, then it seems to want to stall (rpms drop) then it surges to about 2000 and eventually settles back to about 800. Yesterday, it actually stalled on me a few times when stopped.

Anytime the truck is moving, city or highway, I'll feel the truck occasionally hestitate, buck. When it does, I see the check engine light blink off and come back on. I don't see the tach needle move.

Truck has had a constant CEL since I bought it three years ago. I pulled the codes a few days ago, after the problems started, and it had the same two codes it has had for a long time: P1443 & P0420. Truck has no CAT and speedometer doesn't work.

Thoughts??

I'll add that I had a similar issue before that went away after replacing the camshaft position sensor, but that time it was a throwing a code.

 

[runningslow]

No one?

Last night on my way home, the truck actually stalled on the highway... thankfully, I was able to restart it while still rolling. What I really don't understand is how I can go from a good running truck in the morning, to a truck that dies on the highway in the afternoon.

I guess my starting point should be to fix those CEL codes. It looks like this weekend I'll be installing a CAT and replacing the downstream O2. I'll then have to visit a Ford dealer to track down the Canister Purge Solenoid/Flow Sensor Assembly.

 

[runningslow]

Today... today was a disaster. When I left work to go home, the truck would crank, but I couldn't hear the fuel pump prime and it wouldn't start. As I left the key in the ON position, I could sporadically hear the fuel pump relay clicking... eventually it started, but I couldn't keep it running long. I managed to limp it an Autozone, where I bought a new relay. No change. One of the guys at the store recommended resetting the inertia fuel cutoff switch. No change. I had another person recommend swapping the coil packs. Initially that made a change. I was able to drive the truck a few miles problem free, but it eventually started again. The truck smelled like it was running rich. Very strong gas smell.

So... any ideas? fuel pump?

 

[chilsam]

Fuel pressure reg

or Ignition module have you checked for codes

 

[runningslow]

Does my truck have an ignition module? Could it be the PCM?

I'll go get the codes pulled again, but just a few days ago the only codes were P1443 & P0420.

Truck idled fine in my driveway for a few hours.

 

[chilsam]

I believe so

Its up on the front of the intake manifold "silver box" looking apparatus.Sometimes when they get hot they'll shut down the show,there is a special silicone grease that goes on the back side for insulation make sure all the screws are in also.Yes it could be the ECM.

 

[JC 97]

I would replace the o2 sensor and I would check the fuel pressure with a gauge and under load if possible.With the miles you have I would also verify compression in all cylinders to rule out mechanical issues first, before you start looking at electrical.

 

[runningslow]

Thanks for the replies!

Its up on the front of the intake manifold "silver box" looking apparatus.Sometimes when they get hot they'll shut down the show,there is a special silicone grease that goes on the back side for insulation make sure all the screws are in also.Yes it could be the ECM.

I don't see anything there. My Haynes manual only mentions an ICM for the 93 & 94 2.3L. ALLDATA says the ICM is integrated into the PCM.

I would replace the o2 sensor and I would check the fuel pressure with a gauge and under load if possible.With the miles you have I would also verify compression in all cylinders to rule out mechanical issues first, before you start looking at electrical.

In the near future, maybe tomorrow, I'll go buy a CAT and a new O2 sensor. Its been needing to be done, but thankfully I live somewhere without emissions testing!

I'll have to get a fuel pressure tester, but that sounds like a good idea. I'm planning to run a compression test.

Today the truck ran better, but it was also cooler most of the day, since it rained this afternoon. This morning, I disconnected the battery to clear the computer while I installed a new canister purge solenoid and a flow sensor. Hopefully that'll keep the P1443 code from coming back.

 

[Mark_88]

Low pressure fuel pump in the tank is going south...

 

[JohnnyUhlar]

runningslow

i have a 97 5 speed and had a similar problem. except mine died entirely. my suggestion would be to drop a little money into it and be done with it. do all the little things that people suggest but to be honest, get a new fuel pump. if your truck has that many miles on it and counting, its probably tired. i decided to not take any risks and just went all out. new plugs, wires, fuel pump, and fuel filter. i live in south florida so i dont know anything about cold. after i replaced everything, i have a very smooth idling truck and have no problems on the road. also check air. if your mass air flow sensor isnt reading right it could mess with your RPM's.

 

[runningslow]

i have a 97 5 speed and had a similar problem. except mine died entirely. my suggestion would be to drop a little money into it and be done with it. do all the little things that people suggest but to be honest, get a new fuel pump. if your truck has that many miles on it and counting, its probably tired. i decided to not take any risks and just went all out. new plugs, wires, fuel pump, and fuel filter. i live in south florida so i dont know anything about cold. after i replaced everything, i have a very smooth idling truck and have no problems on the road. also check air. if your mass air flow sensor isnt reading right it could mess with your RPM's.

I know what cold is... I grew up in Michigan. Thankfully, I live in central Florida now, so I don't have to try starting this thing on a cold morning. However, right now we still have a 20 degree swing between the morning and afternoon.

Thanks. Fuel pump is on the list. Today I ordered a Magnaflow direct fit cat and new O2 sensors from Summit. Fuel pump will be the next investment, but I've got to see if I can get those bed bolts off first. When I get some time, I'll clean the MAF.

I didn't drive it today, so we'll see what happens tomorrow.

 

[runningslow]

Any recommendations for a new fuel pump?

I'm wondering if I should just pull the bed to inspect the wiring to the pump first?

 

[Mark_88]

Pulling the bed would be a good place to start...but I doubt that it is wiring related...I'd have a pump on hand new or used to swap in if you're going that route...might as well get it done so you don't have to do it again...you can always return a new pump if it is wiring related...as long as it hasn't been installed they will take them back.

 

[runningslow]

Before I leave work today, I'm going to jump the fuel pump relay.

I figure if the pump runs fine and I can drive it that way, that should rule out the fuel pump and probably indicate that wiring is bad from the relay to the PCM, or the PCM is going bad.

If I still have the same problems, then I think it would be safe to assume that the fuel pump is bad, or that there is a wiring problem from the relay to the pump.

 

[JC 97]

Did you check fuel pressure with a gauge? It is pretty easy.You can guess all day but if you don't systematically check first you will just throw parts at it.I prefer not to guess.