Cold Weather Idle Problem

For a while I have been having a problem with my truck. The check engine light comes on intermittenly and goes off in a few days. I put my truck in the shop at the dealership and they claim that the computer didn't pick up that the light has ever come on.

Here's my problem: whether or not the light is on, upon start up, the truck will rev up and down, fluctuating between about 750-1500 rpms and keep revving up and down, back and forth, however you want to call it instead of staying at one rpm. Think as if I were pressing the gas and manually revving up the engine, but instead it's doing it by itself. When the truck is running fine, it usually will idle in park at about 500 rpms. Also, when I am driving at a steady speed, the engine will rev up as I am drving. For instance, if I am drving 60 mph, the typical rmp is around 1500. However, it will jump from 1500 to about 1700/1800 and back down again. And when I am slowing down to stop, the truck will rev up and lurch me forward and will also jam into gears when I am switching between drive, park, reverse, etc because it's running at too high of rpm.

Help! I love my truck but it's been in the shop twice and no one will tell me what is wrong.

Is your truck consuming any unusual amount of oil? If it is, the gasket on the bottom of the intake manifold is leaking causing very high idle at startup and when warm. See any smoke when you first start it up?

My 2002 Dodge Ram has 36,000 miles, small V8, 2WD, with no prior problems. When I am in park or sitting at a stoplight, the idle fluctuates up and down sometimes to 2 rpms. This is with or without the a/c on. It can be any time of day. I took it to the dealer and they said it was a dirty throttle body and worn spark plugs. After paying them $510 to clean the throttle, install new plugs, & reprogram the computer, 3 weeks later I have the same problem again. They said it could be something underlying that they didn't see. I would appreciate some help before Thursday because I am going back to the dealer and cannot afford to keep paying them this kind of money! THANK YOU FOR ANY HELP!

Try putting a new idle air control valve on and see if this fixes youre problem. It is located on the back of youre carbarator.

For about the past 6 months on and off my truck will start acting up. It will Run rough Like it wants to stall and any gas worsens the problem Unless I floor the gas it wont get any acceleration. It happens for a while then stops for a few weeks then starts again. The Engine light is coming out to be a bank 1 sensor 1, O2 sensor which I have replaced twice now.I also put a new coil in. The most recent time it seems like my throttle is sticking also causing me to accelerate without touching the gas. When I do touch the gas it start to run rough like it wants to stall. Im out of ideas as my truck does not have an auto choke which I thought might be the problem. Silly me lol

Hello, I have a 2001 Dodge Ram 1500 with the 5.2L. It starts fine drives fine; however, in park the engine idles up and down from around 700 rpm to 1200 rpm and is worse at cold start. When it warms up it often stops; however, occasionally will do it after driving distantly and restarting. There are no engine lights on, and we tested the computer with my Actron OBD 2 pocketscan tester whith indicated no codes, and the three - key turn indicats "PDONE", furthermore, there are no dash or engine lights on. Can anyone help me with this?

No. How do you check them? Can a sensor be bad if theres no engine light on?

No. How do you check them? Can a sensor be bad if theres no engine light on?

The "TPC" is clearly good because the engine became very hesitant and bogged down when I pressed the throttle, and the check engine light came on. I then cleared that code and the check engine light went off.

I then started over with checking the "IACV" and when I unplugged it, the engine continued running with no changes whatsoever, and no check engine light came on, so I pulled the "IACV" and cleaned it as well as the "IACV" bore, which had a lot of carbon build-up. Upon reinstalling the " IACV" I then started the engine and unplugged the "IACV" again, and let it run for several minutes, and upon killing the engine and restarting it, the check engine light came on; however, again there was clearly no change in the engines operation. I again cleared the computer, re-plugged the "IACV" and started the engine, at which time the check engine light was off and it stayed off. So, I suspected the "IACV" was bad as you suggested, and I ordered one. Upon receipt of the new "IACV" in a few days, and getting it installed, I will let you know how it does. I appreciate your assistance and hopefully this works because I just purchased this truck and got a great deal on it; however, I really can't afford putting much more money into it anytime soon. Thanks again, Shannon.

Joe, the tps and the iacv was bad. The tps was making the transmission shift in and out of gear.

Yes the truck runs great. The TPS was most of the problem. Thank you for all your help

Idle surges up and down after idling for a few min.