Idles fine. Just rebuilt the engine myself. No smoke. I can hear the fuel pump engage when I put the key to the on position. If I try to give it much gas when driving or go up a hill it sputters and lurches. But not when parked and I increase the throtte, it runs fine then.

New rings and heads. New cam and bearings. New lifters and rods. New timing gears and chain. Timing marks checked again. No leaks apparent internally. Don't have a fuel pressure gauge yet. Thats next. No check engine light yet. It had the same symptom before I rebuilt it. Vehicle sat for 3 years before I rebuilt it. New gas (11 gal) filled today. Coil seems to ohm out fine. I'm getting spark, I tested each wire with a timing light. Drove 25 miles so far. Forth and fifth gear seems to have the hardest time. But it happens in second and third also.

Questions.
Will a clogged cat cause this. Its original. 18 years old. Mufler blew out an old wasp nest and other crap when I started it up for the first time.

Injectors?

Fuel Pump just not cutting the mustard any more?

Is this something that will happen until the rings seat or the engine breaks in?

Bad sensor? MAF or something else?

Thanks.

 

Well with it reving ok when at rest, but wanting to cut out under load, makes me want to suspect a spark problem.

Maybe excessive spark gap, or a weak spark from leaky or high resistance plug wires or coil, or other ignition component.

If all that checks out & seeing as how this ride has been in storage & you had stuff blow out the tail pipe, why not have a good look at the air intake side of things, to see how the air filter is, or if some critter has built a nest in there, so check the air intake ALL the way to the inner fender, to make sure it's clear.

Then maybe hook up a vacuum gauge & see what it has to say.
From it's readings you can get a feel for engine compression, exhaust back pressure, timing, ect, ect.

I agree a proper fuel pressure test would be a good idea.

A bunch of thoughts for pondering.

 

If what you blew out looks like an old wasp nest, possible your cat spewed its guts..What engine is this??? If this is a push rod engine, did you go through the sequence of turning the engine to certain timing positions when you snug up the rocker arms?? Also, very possible the injectors are sticky-gets a little pricey at this point..The MAF should give you a code if its really bad-try cleaning with the appropriate spray-DO NOT TOUCH THE ELEMENT WITH ANYTHING BUT THE SPRAY!! Go back and check for intake leaks(carb spray), and for vacuum hoses you might have forgot to put back on.. How good is the fuel line from the tank?? Could have a clog in the line..Let us know how this comes out!!

 

It could be a clogged cat or even a clogged fuel filter. I had an 84 ranger with a 4 cylinder, it would idle all day, but soon as you put it under load, it would sputter and die.

 

Thanks guys. Fuel pressure is in range. 38 PSI. I'm thinkig the Cat. It's the original O2 sensor also, but would that affect it this much if it was bad? Hate to think I have bad injectors. Plugs looked good. Need a backpressure gauge to check pressure before the cat. NAPA didn't have one today.

BTW its a 4.0 fuel injected engine. Forgot that on the first post.

 

You can check back pressure with a vacuum gauge.

 

Hey Pipe Burn, I am having the same issue and I am thinking the O2 sensor. Have you tried this yet? I replaced my plugs and fuel filter and still have the issue. I would like to know if you found the issue and what it was. I will be hoping to replace the O2 sensor this weekend.

 

Power issue was resolved with a new cat. Don't feel like its towing something any more. Tried new plugs and swapped out the coil with another ranger owned by my son. New PCV valve.

Still diesels and hesitates or cuts out and bucks with more than a 1/4 pedal, not really an issue in 1st, not too bad in 2nd, worse in 3rd, but gets noticably worse in 4th and 5th gears. . Trying a O2 sensor today.

Took the spout connector out and checked the timing. It's at 10 BTDC. Noticed that doing so did not trip the check engine light like it will on the my 96 Bronco. If that's normal, fine. But it makes me wonder about the ignition control module or the PCM. How do you check to make sure the PCM is allive. Will it not run if the PCM was bad?

If the PCM stopped functioning correctly, would it run on the old data from before the rebuild when it ran like crap? Just seems like it isn't compenstating or learning the new engine. Are you supose to reset the PCM after a rebuild? Something other than just undoing the battery for 20 minutes?

So is it a sensor? My new Alabama Cylinder Heads out of spec? Or am I just impatient and should just drive it until the computer compensates and the engine breaks in.

Currently 150 miles driven on the new engine.

 

I dout it's the computer needing to be reset, but just undo the battery for 20 minutes and see. Try having the injectors presure cleaned. The truck in no spring chicken, so the puter could be malfuncioning. The truck can still run with a bad PCM, it just won't run correctly or not at all.

 

I'm sure this isnt an issue but one night 11 pm or so on a long cruise home my engine started to chug and a total lack of power. Pulled over could not see anything due to the darkness. So i took my time getting home, got home alright. Next day went out there and noticed the spark plug wire had came lose off the plug. Put that back on there and off she went again. Now it sits with a bad intake manifold gasket.