Ok, I need as much info as anybody wants to throw at me! Good, bad or indifferent, I'll gladly take it!

Here's the scoop. I have a 98 Dodge 1500 4 x 4 with the 5.9 in it. The engine USUALLY runs good. Every once in a while I was getting the ocassional "bucking" (once or twice every 3-4 hours of driving at highway speeds).

All that changed yesterday. It went into a monkey motion on me! It started surging, in idle with the truck in gear. It was pushing against the brakes! When I pulled out into traffic, it wouldn't pick up speed. Misfired, farting and burping all over the place. I eased it over. Turned it off for a few seconds, started it up and it ran ok. Went and painted a Harley tank , started it back up and it did the same thing at a traffic light, but I kept it running and after about a minute or two, it ran fine. Brought I home, shut it off, started it about 10 minutes later and got the following codes:

1) - P0108 - Manifold Pressure Circuit High - I pulled the MAP sensor off the throttle body, metered it and put vacuum on it, it checked out good!! Everything was where it was supposed to be!

2) P1297 - No change in MAP from start to run!

3) P0132- O2 Sensor circuit High voltage Bank 1 - Sensor 1 - I replaced both O 2 sensors three weeks ago with new NTK!

4) P0133- Sensor Circuit Slow response - Bank 1, Sensor 1- Again I replaced Both O2 sensors about three weeks ago!!

Anyways, I cleared the codes after checking the MAP sensor, ran it in idle for about 4 minutes and it starts farting , snotting and burping again. SO, I change out the PCM. ( I always keep a spare!!) After swapping the PCM m another 3-4 minutes running in idle and it does the same! Shuddering, RPM wanders up and down ( about 50 to 100 rpm) , finally drops off to the dieseling stage, and then picks back up to about 625-650 rpm. It does this with BOTH PCMS.

Now, I 've replaced the crankshaft sensor with new, The inductive pick-up with new, the coil with new, and the spark plugs. I have a new distributor cap and rotor to go in, as well as new spark plug wires.

I drove it to the dentist this morning and I have very little play in the accelerator.The acelerator travel is very small, maybe an inch from full up to floored. ( I haven't touched anything on the accelerator cables!) The maximum I could get it to go to , driving was 2k RPM. I'm stumped!! The compression is great, I can't find any broken vacuum lines nor fittings!

I'm up the creek without a paddle on this one folks!! Anybody recommned anything I may have missed, over looked??

I'm headed out to the driveway to start beating it with a sledge hammer!!LOL LOL

 

I suggest you read the plenum sticky.

 

Zman: Thanks. I can't see it being a plenum gasket though. It's an erratiuc problem and from my experience with thrucks (this IS my first Dodge though) plenum gasket problems are constant. The problem I'm having is erratic. It starts and idles fine until it warms up. Then it goes into a monkey motion!

I did install a new distributor cap, rotor and wires. No difference. I swapped the PCM, no difference. I cleared the codes yesterday, drove the truck around town and the back roads a bit. The sputtering came back for a short period of time, then went away and the truck ran fine. After being home a half hour I started it again, it went apr again in less then 5 minutes, then it smoothed out.

If th eplenum gasket was FUBAR'd, 1) would the engine not run like crap all the time??? and 2) would this leak show up on a vacuum test? If so what should I be looking for??

The truck DOESN'T have a CAT on it. We're NOT required to maintain them here!!

Thanks

 

To me, the problem seems to follow a sensor. I would find a jy MAP sensor and replace that bugger and see what happens.

 

Dodge Dude: Thanks, I metered the MAP sensor. It checked out find. Wiggled the wires with a meter on them, with vacuum on it and it checked good. Even did the 'fail-safe" screwdriver whack on it. It checked good. I'm thinking that I'm gonna yank the plenum off it and check it anyways! I have the time so might as well fix everything I can, while I can!! LOL

 

Has there been much maintenance performed on this truck? It sounds as though it may have a short in a wiring harness and/or a bad part - distributor, idle control, timing bouncing (slack chain/gear set), fuel pump dying, etc. come to mind with this type of issue..

 

Atomic Dog: No just the stuff that I have listed as being done. I don't let anybody touch the truck, except me. I thought of some of the things you mentioned, but as I stated, it's an intermittent thing.

The accelerator thing was just that the cable was popped out of the little plastic cam doo dad on there. My son was "helping" me and he may have yanked on the cable. I put it back so the pedal travle is back to where is should be.

I checked all the sensors on the damned thing. It's getting power to and ground through the PCM so everything is working as it should.

I oredered the Hughs aftermarket plenum rpeair kit. it SHOULD be here this afternoon, via the Loser Cruiser ( greyhound). I'm piddling with disassemblingthe thing right now. SO IF the parts get here this afternoon, I'll have it ready to go back in.

If I find anything, I'll post here!!

Thanks for your help folks!!

 

Since when does GreyHound deliver parts?

 

My thoughts exactly.

 

^^^ The GrayDog delivers damn near anything within reason, I get parts shipped via Graydog all the time, Campground supplies and truck parts.
Op good luck today with your planned work.