'93 Ram D150 5.9L 2WD Automatic

I have been searching on this forum for hours and have done just about everything that can be done for this problem except just replacing the engine. This started about 6 months ago I was in a field coming back from hunting. I turned the truck on and put her in a drive, pressed the gas, it started to move then stalled. I thought that was pretty weird really didn't think much of it till it did it again a few weeks later. Now it has gotten really bad to wear the RPM's will drop below idle or stall after barely pressing the gas and letting go. After it drops below idle it will catch itself and idle at normal RPM, every now and then it stalls, but it did it twice today. I have sprayed Seafoam through the intake, I have replaced the fuel filter, fuel pressure regulator, TPS, MAP, and IAC. The IAC made a pretty big difference to where now it only drops RPM's and does not stall on me. At least it hasn't yet, I just replaced that today so its hard to tell. I am starting to think maybe the throttle body needs to be taken off and cleaned up real well since the IAC made the biggest difference. Any other suggestions as to possibly what could be wrong or should I adjust the idling speed and forget about it?

 

For starters, the idle speed is controlled by the computer and is not adjustable unless you jerry rig it. You may have one or more injectors sticking. You have MPFI (multi port fuel injection) so spraying Seafoam in the throttle body does very little. Dump a full can of Seafoam in a full tank and run it thru to try cleaning the injectors. You can also use a piece of hose from your ear to each injector to see if they are all firing properly or at least the same.

 

The last time mine was doing that (about 2 months after replacing the IAC) I replaced the over 7 year old battery and that cured it.

 

i don't think pouring the sea foam in the throttle body will do anything except make it end up in your oil if you have a bad plenum gasket.

 

Just thought, mine is OBD II. Might make a difference, I don't know for sure.

 

Assuming he was spraying Seafoam in his throttle body while it was running. The Seafoam will clean the throttle body throat, the throttle plate, the inside of the intake, and attack any carbon on the top of the intake valves somewhat. These things should not be causing the stated symptoms. If he had a bad plenum gasket he would be sucking crankcase gasses into the intake and the cylinders and would probably be blowing blue smoke and fouling plugs.

 

How does it run once you get it going? Is it hard to start? Does it have full power? Have you checked the camshaft position sensor? Have you checked the EGR valve/system?

 

I was thinking that could be the case. I have read somewhere that could be an issue. It seems like the lights and power windows have not been getting as much power as they usually do. I am not expert mechanic, but I think that might be the case. I will post back later on the results.

I have put seafoam through the intake, gas tank, and cleaned the throttle body this morning and still nothing so I hope the battery is the problem.

I know it is not a timing issue because I am not getting any backfires or funky colored smoke. It starts and idles fine.

 

The truck is not hard to start and it runs fine once I get it going. It does have full power. I replaced the EGR Valve a little over 6 months ago, I guess it would not hurt to check it again. I have not checked the camshaft position senosr. I have tried looking for one online but could not find one. Oreillys, Advance, or rockauto.com does not have it. Any suggestions for where?

 

Can't help with where to get one but you can test the one you have.