Hard to start. Idle surging up and down. Won't stay running.

[Glennjames]

1999 dodge ram van 3500 5.9 liter gas engine. Replaced plenum gasket. Ran like a top for two weeks, until I put fuel injection cleaner in it. Two days later , idle is very rough, up and down. Stalls after a min. Stalls as soon as step on peddle. Replaced IAC still no change. Replaced fuel pump assembly. No change. Not showing any codes. No vac leaks that I can find. New cap , rotor, plugs, wires. No change. Reset pcm. No change. Changed cat and muffler. No change. Anyone have any thoughts on this. Please help.

[alloro]

Vacuum hose fell off, intake gasket stopped sealing, crank sensor, MAP sensor, or TPS went bad...there are many possibilities. Considering the up and down idle I would start with looking for a vacuum leak.

[Glennjames]

Going to go over all vac lines after work . Should the map or the have a vac line?

[alloro]

The MAP sensor is mounted to the front of the air intake horn. You won't see much of it's vacuum line because it is very short.

[Glennjames]

All vac lines check out. Cleaned throttle body, installed new gasket. No change. IAC doesn't seem to function correctly, what controls the IAC? Also should I be able to rotate my injectors left to right at all. The one on cylinder 8 moves pretty easy. Swapped fueses around to see if anything changes and no dice. Should theTPS move the butterfly? Or does it just relay info. Just so you know I greatly appreciate your input with this. I'm going to order the GPS this pay day and keep fingers crossed.

[alloro]

Originally Posted by Glennjames

IAC doesn't seem to function correctly, what controls the IAC?

Also should I be able to rotate my injectors left to right at all.

Should theTPS move the butterfly?

The PCM controls the IAC. If the IAC isn't working then it might need a good cleaning or just replaced.

Yes injectors can turn, they are held in place only by rubber O-rings on the top and bottom.

The throttle shaft moves the butterfly and the TPS. The TPS is nothing more than a variable resistor that reports how far the throttle is opened back to the PCM.

[Glennjames]

Thanks for the info. The IAC is New. So I'm leaning towards the TPS and glogger injecters. And I believe my timing is off a bit. For good measure, replacing the pickup coil. Again thank you.

[alloro]

Originally Posted by Glennjames

And I believe my timing is off a bit. For good measure, replacing the pickup coil. Again thank you.

Ignition timing is computer controlled and IS NOT adjustable. The pickup coil controls fuel injector timing not ignition timing. The distributor should never be turned and if it has been requires the dealer's equipment to correctly set it.

[Glennjames]

Originally Posted by alloro

Ignition timing is computer controlled and IS NOT adjustable. The pickup coil controls fuel injector timing not ignition timing. The distributor should never be turned and if it has been requires the dealer's equipment to correctly set it.

Yeah about the ignition timing😂 I moved it. A few degrees. Hooked a code reader up. P0117 P0118. P0443. P0122. P0123. P0107. P0108. P0753. P0112. P0113. P1391. P1764. P1765. Safe to say it's time for an overhaul. Lucky me. Thanks for all your input. Would have been lost and causing more issues for myself. Putting my 1981 D250 back on the road until van is back to par. I will keep you posted. Thanks again.

[alloro]

Several of those codes indicate a serious vacuum leak. Are you sure the plenum sealed properly when you re-did it?

[Glennjames]

Yes. 100% sure it sealed. Haven't had any oil consumption since. Before replacing the plenum, 1qrt of oil per day. I was driving 300miles round trip every day.