Good day to all! I humbly ask your opinions on my situation.

When my truck has been running for a while (half hour - 45 minutes) it starts to buck and cough terribly when I give it even just a little gas. Sometimes it will straiten out while I'm still driving it and run fine again. If I pull over and shut it down for 15 - 20 minutes and then start it back up, it runs fine. I tried shifting to nuetral to see if it was engine or drivetrain and it continued to spit and pop. My CEL came on so I took it to my mechanic to diagnose it while it was in the middle of it's fit, and he couldn't get his Snap-on diagnostic computer to communcate with my truck. Not only does it run like crap, but it doesn't want to talk about it!! I've got a code reader coming from ebay to try to get some codes myself. It's a '98, so the self diagnose thru the odom doesn't work. A fact my mech didn't know.
I recently had the Cranksaft Position Sensor replaced. (It was producing an intermittent stall at temperature.) Doesn't stall anymore.
I've been cruising the forum, and I think I'll start by cleaning the O2 sensors. (Easy stuff first!)
Anybody have any other ideas? I decided to try this myself because my mechanic wanted to keep it for a couple of days to diagnose it, which would equal another $500 repair bill.
Any help would be appreciated.

 

Sounds like the fuel pump could be cutting out. How many miles are on the truck? Also, does the CEL light flash? If it does, that's an indicator of a misfire. Misfires can be caused by a number of issues, one of which is a clogged catalytic converter.

 

Sounds a bit like my problem- I will put up a posting with my similar issues on my 98. I have a feeling mine is tranny related....

 

It's got 115k miles. I bought it used at around 60k, so I can only assume it's the original fuel pump.
Would a faulty fuel pump produce a code? Is there any way to test to possitively I.D. that as the suspect?
The CEL did flash at one point but it is not flashing right now. Sitting in park and bringing up my rpm's just a little I can feel a little skip, but nothing like the spitting and sputtering when it's in its fit.

 

Hmmm, if could be the catylitic coverter. Do you have any rattles coming from anywhere? When the cat gets hot it could start falling apart more or choking out the engine.

Also could be the fuel assenbly as said. Sometimes fuel filters get clogged after they've been running for a while. Then you turn it off and all the crap settles back down to the bottom. I'd check the fuel presure then maybe look at the cat!

 

Right on about the fuel filter. The Dodge fuel pump assys have a screen (sock), an internal filter, and the pressure regulator. Here's what my pressure regulator looked like at 114K.


The pressure regulator acts like a third stage filter. Taking the truck to a muffler shop to have the cat pressure checked wouldn't hurt either.

 

I'll work on getting the fuel pressure tested right away. As soon as I get some numbers I will post them for review. I appreciate the help.
Time to head off to work.

 

My CEL used to flash and have a misfire due to a clogged cat

 

The fuel pressure test numbers are in.

Engine off 0 psi
Key on, (pump whirring) 30-40 psi drops back to 0 psi
Engine running 50 psi
In the middle of its coughing / bucking fit fluctuates between 40-50 psi
Engine off 0psi

That explained also why it would sometimes crank for a couple of seconds before it fired up.
I ordered the new pump this morning after the test. Wouldn't you know I just filled it up on Sunday! I plan to change it this week -weekend. I'm negotiating some garage time with my brother-in-law now!
I'll let all know how I make out.
Thanks, Tim

 

My truck did the exact same thing... turned out the o2 sensor heater fuse was blown since the wiring shorted out against the tranny case. replaced the fuse and the problem never came back. yank your o2's and look for any wiring issues on it. if you dont see any, you can try cleaning them but I would consider replacing them if they've been in there a while (60k or more miles).