Sputtering With Load

[avenger]

1991 Ranger 2.3 Was sputtering when cold at about 1500 rps in whatever gear unless your cruising especially when climbing hills in 3rd gear around 25 and 1500 rpms Changed the coil, wires, and plugs and its still doing it..what else could be causing this only around a certain rpm or when under load? It like a slight missfire and just feels like the truck jumps a little and regains power after a half a second.
EDIT: it also seems to do it way more when it's cold vs when it's warmed up
Thank you for your help,
John

 

[tomw]

Maybe have a fuel delivery problem, leading to 'lean' misfire. Climbing a hill calls for more fuel than cruise, and cold operation is generally 'helped' by the computer adding more fuel because it won't mix & burn as well when the air/engine are cold.
Check pressure and delivery at the schrader valve on the fuel injector rail using a pressure gauge. Some auto parts stores lend tools with a deposit. Calculate volume over time by catching fuel in a container and doing some math. If low volume, it may be the filter, pickup in the tank, or fuel pressure regulator. If low pressure, the pump is more suspect.
tom

 

[avenger]

I'm thinking possibly the same thing.. I was gonna change the fuel filter on Friday when I get paid anyhow just because it probably needs done anyhow.. But it doesn't seem to do it when going full throttle and getting it up in Rpms.. It runs fine then it's just right off idle when taking off or going on a load at lower Rpms.. But I think the fuel filter is a good idea

 

[RonD]

Also clean MAF(mass air flow) sensor, dirty MAF sensor is a common issue for stumbling

 

[avenger]

Also clean MAF sensor, dirty MAF sensor is a common issue for stumbling

I did that a few months ago but I'll do it again.. Can't hurt any.. I still have some maf cleaner luckily

 

[tomw]

Okaaay. I am confused as to what the symptom is.
Take off from idle, accelerating, or at cruise speed?

The MAF can give different symptoms, but mostly will show up when you try to accelerate or change speed. There may be an 'empty' spot, where it seems the engine is not responding to the gas pedal input, but then clears up. A fuel delivery problem would show more when trying to climb a hill, basic load condition, a 'long pull' more or less.
tom

 

[avenger]

It just like sputters off and on mostly at low rpm.. Mostly taking off from a stop or if it's a low load.. Like let's say I shift to 3rd gear at 20 mph and put my foot maybe 1/4 or so the way down on the gas.. It will miss slightly every now and then.. It's not constant. It's just a slight sputter every now and then.. Or if I'm going up a slight hill at 25 in 4th and give it the same amount of gas it will sputter slightly.. It seems to be between 1500 and 2000 Rpms most of the time too.. Full throttle if you're getting up in Rpms it does not sputter

 

[tomw]

That description sounds like misfire due to 'lugging' the engine. If you look in your owners manual, it may tell you the 'range' of speeds you should use for each gear. I don't think being in 4th at 25mph is recommended, but if it is, you cannot expect quick acceleration, and you will get misfire of the spark plugs ... and I can't remember the term. Anyway, the plug is harder to fire under high pressure, and that type of operation creates high pressure. What shape are your plugs in?
The solution? Downshift.
tom

 

[avenger]

Plugs only have probably 1000 miles on them.. And it never did it before until a month or so ago.. And it was running fine with these new plugs and it even does it when getting between 1500 and 2000 in first gear on flat ground

 

[tomw]

ave:And it was running fine with these new plugs and it even does it when getting between 1500 and 2000 in first gear on flat ground

That is a totally different situation.

Have you checked for water in your fuel? That can cause intermittent misfire, which might seem to get better if you back off on the gas pedal. Water can 'come and go' as it is picked up by the pump and delivered, and then normal fuel is supplied ... and back and forth as the water comes and goes.
What does it do when you climb a hill? That would cause more fuel to flow if the engine was running properly, and would tend to make a fuel problem show up more.
tom

 

[avenger]

Changed the fuel filter.. No change still feels like it jumps and stops for a second and catches itself as it's going down the road at low speed and rpm

 

[avenger]

If it helps here is a short video of what it is doing.
https://vid.me/9sCm

Also the MAF sensor seems to be loose and can be moved back and forth in the tube.. I tried tightening it but the bolts seem messed up because they are really tight to turn and not pushing the sensor into the housing like they should... Could this cause this problem?

UPDATE: I unplugged the maf to let it go to the stock air fuel mixture.. It was better but not perfect.. So I plugged it back in and unplugged the Tps and it was better running than the other but not perfect.. I am wondering if it is a mix of the two?