Hey, I havent posted in a while. Got some great info last time.
I still have one problem with my truck (94 Ram 318 Auto 2 wheel drive short box).
Anytime Im driving over 60mph and let up on the throttle (for traffic, or goin down a hill) it shutters and bounces around. It feels like a misfire or loss of fuel pressure. Its been doing this since day one.
I have replaced; Ignition- Plugs,Wires,Cap, Rotor and Coil. I have check them all countless times. The gapping in the plugs, the wire route so they arent crossfireing.
Ive ran a fuel pressure guage on it and its perfect. No problems. No change accross the board. The plenum has been done by the previous owner. I checked it and it seems to be fine. No signs of any problems with it. The tranny works fine, aswell. Ive changed the fluid, and did not flush it. Same with rear end.
Only thing I havent replaced is the fuel filter. But with there being no change in pressure, I figured it must be ok. Mind you the fuel filter, and pump are the only things I havent changed.
Im looking for some advice. I can not figure it out.. I dont feel like replacing the fuel system just to eliminate that as a possiblity,yet haha.
I thank everyone in advance!
Happy Easter As Well

Memphis

 

if the fuel pressure is ok while driving, and since the fuel filter is integrated with the pump, inside the tank... i doubt that's your problem.

you can check fuel pressure 3 ways. at idle, while driving, and about 10-15 minutes after shutoff (to see if the injectors are holding pressure).

i don't understand what "shutters and bounces around" means.

 

Glad to see you came back, well as far as the fuel pump and fuel filter they are one in the same, we dont have filters you can change. Ours are none serviceable filters they are built into the pump and there is two total.

The only thing i could suggest is maybe check your cat, possibly when the previous owner changed the plenum he didnt change out the cat. Usually when our plenums go they clogged the cats up and take them with it. I would consider pulling the pre cat O2 sensor and try running the truck like that to see if there is any improvement. It will be loud but if the cat is clogged pulling the o2 sensor will reduce the amount of back pressure and maybe help level out your issue.

Also i would take the injector's out and clean them by hand, in fuel system cleaners dont always do the job they are supposed to, if you do decide to pull the injector's make sure you dont damage the O ring because you will need to have a perfect seal when you put them back in.

I hope some of this will give you atleast a few options to look at, goodluck and remember to post your results. Good or bad

 

Don't overlook purely mechanical.
Failing Ujoints can create all kinds of shuttering problems at different speed ranges, as can lose/missing motor mount bolts.

Probably not your problem, but both are well worth checking on at least a few times a year.

 

Thanks for the feed back.
The cat has been changed, and a new 02 sensor installed.
Fuel pressure was fine at idle and driving. I did not check it after letting is sit. I think I may take the injectors out and give them a good cleaning.
As for other stuff causing the "shuttering". I cant see it being the u joints, but thanks for the advice!
When I said "shuttering" its like the truck is running out of fuel. It bounces around and backfires. I cant really describe it better then that, sorry.

 

cps.?


1fast2liter had about the same problem try to pm him

 

Crank Position Sensor? Someone did mention that before, but I didnt think that would be it. Ill drop them a line thanks!

 

I dropped 1fast2liter a message and he said it was his O2 sensors..
Question I have, where are they both located? I have no cat and only see one sensor. I looked all around for the second harness and couldnt find it...
Im gettin a different exhaust put on Monday to help solve the problems. But while I was under the truck, I unhooked the O2 sensor and went for a drive. The truck did not drive any differently. Nor did the check engine light come on..
Will the code reader tell me if its my crank shaft sensor?

Thanks again!

 

you only have one in your truck. The coade reader will only tell you something if you have a CEL.

 

memphis, how hard are you on your truck? not that you are doing anything wrong but I think there are some learn values in the pcm that can cause this. try resetting the pcm and driving like a grandpa for a week and see if things get better. My truck was originally bought by me for an employee to drive, he was busy, always in a hurry. when I would drive the truck after him it would do what you are describing until it got used to a more relaxed driving style.