For Sale... 98 Dodge Ram 1500 4x4 318
New: Speed sensor, Brake computer, Crankshaft Position Sensor, Fuel Pump, Oxygen sensors, Catalytic Converter.
Has an engine bucking problem when warm, no codes though. Need to sell... causing severe headaches!!!
Just kidding... about the selling it part! I haven't put the Flowmaster on it yet, should arrive Monday. I'm gonna have a old friend (that I haven't seen since a mutual friends wedding) put it on his diagnostic computer Monday night to check the PCM. Not sure what else it could possibly be. I swear I'm not making this up... everything that was changed really was faulty! After I changed the cat and it continued to buck, I questioned the old cat. It rattled like a coffee can full of half dollars, so I know it was gone!!
Not that it caused the symptoms I'm experiencing, but I even checked the voltage through the TPS, and that was within spec.
Was going to check the other sensors around the TB, but figured Todd's gonna hook it up anyway, he can check the voltage while it's running.
Any other thoughts? I'm open to darn near anything! Tire pressure, ashtray lightbulb. I always buckle my seatbelt and keep the glove box closed. [sm=dontgetit.gif]
Tim

 

timing? maybe a bad crankshaft position sensor?

 

That crankshaft position sensor has me wondering as well. It was changed by the garage, for an intermittent stalling problem (only during warm engine, also). After they changed it the truck hasn't stalled but did develop this bucking problem.
I think that two of the things I want Todd to hone in on are that and the camshaft position sensor (a timing sensor). It just doesn't make sense that there is no misfire code. (It bucks hard!!) Makes me think the PCM might be faulty, just hate to change it without being sure. Can anyone recommend an ebay outlet for pcms, in case it is bad?

 

pulled this from another thread

i think that i read that the crank sensor is really sensitive. maybe the new one was just a little banged up. did you have the problem before? did it start right after you got the new one?

 

The bucking problem started after they replaced the Crankshaft Pos. Sens. for the stalling. I didn't notice it right away, because I don't always drive it long enough (30-40 minutes) to get it to do it.
I'm thinking if it's a sensor, it can be when the PCM is going into closed loop mode and recieving some bad data, then telling the injectors to make a change that is causing the buck. Or, the PCM itself is bad and when going into closed loop, itself is making the changes that cause the problem. It never does it on a cold engine.

 

Got the new catalytic converter and Deltaflow 40 Series on. Sounds great. Quite loud! However the new cat didn't solve the problem. My new mechanic is going to take the fuel rail and injectors off for a good cleaning. He noticed a TSB (about dirty fuel rails) on my truck while he had it on the Genisys. I'll post results as they come.

 

Hey, I’m new to the forum by getting (what I think) was a good deal on an ’00 5.2L 4x4.

I hope you have the problem fixed, just wanted to share my relief to a similar problem on a GM 3800 typeII. Only when it would warm up would I get the bucking problem. I was told it could be cracked wires and when they would heat up they would foul out. New plugs and new wire set and never had the problem again. I really don’t know if it was the plugs or wires, but it never happened again.

If you have not fixed it yet, hope it helps.


B.T.W. ..... does anyone know if that plenum leak is a problem for the '00 too?

 

Thanks 1shooter, for your input, and to all who have responded. One of the things we did to try to remedy the problem was a full tune-up. Plugs, wires, cap, rotor, air filter. My new mech (a certified technician friend) pulled the injectors and cleaned them and the fuel rail. Still no joy. While it was on the Genysis, I did notice that while it was bucking and coughing (in park), it did not show any misfires, and all the injectors were working. The TPS, IAC, MAP, O2's all showed working within parameters (at least electrically). I ran 2 bottles of Chevron Techron over 1 1/4 tanks of fuel to clean the injectors. I dumped in a bottle of Isopropyl to clean up any water that might be in the tank. No joy. There's another injector cleaner that connects right to the fuel rail that Todd wants to try next. We're still working on it!

 

Sounds like the same problem I'm having with my 95 2500 v10. Changed the plugs and if was fine for a week. Now the problem is back. Checked the coil packs, they show no resistance on the primary side, but they were working. Truck ran perfect for 135k miles, first major problem so I can't complain. Just frustrating trying to track it down.

 

Guys, could it be the idle air sensor on the throttle body? Don't know but just an idea. I can't imagine it'd be the PCM. It's got to be something feeding the PCM bad info imo.