Engine dies at idle, even with new fuel pump. HELP!

First, my truck began idling real low around 300-250 rpm along with low oil pressure light. Now it won't even stay running unless I keep my foot on the gas! When I press on the gas pedal the oil pressure goes back to normal range and oil pressure light goes away. However, as soon as I let off the gas it drops to zero and dies.


I thought it was the fuel pump, so I went ahead and replaced that. Replaced air filter. I believe i'm getting good fuel pressure from the pump because I put the fuel line in a plastic bottle, cranked the engine over and a generous amount of fuel poured into the bottle. Also, I tried cleaning my fuel injectors and still the same problem. When I rebuilt the motor (about 400 miles ago) I had replaced the Idle Air Control Valve on the throttle body.

I'm starting to think either 1) my timing went screwey, 2) I bought a cheapo Idle Air Control Valve that got stuck, 3) I need to check the throttle position sensor.



Any comments, questions, or concerns will help. Thanks ya'll!

I would be checking the operation of the IAC valve.

Pull the brake booster line and start it. Oil pressure drops like a rock below idle, I wouldnt worry about that. Pulling the brake booster line will allow for airflow despite a bad IAC. If it runs nicely with the brake booster line off, i'd bet on the IAC. One of my old friends from school bought a gen 2, its beat to hell, his IAC was bad, despite my warning of cheap replacement parts, put a chinese IAC in there. What do you know, its bad again.

So now he's driving it without power assist brakes...

dudeman2009 said:

Pull the brake booster line and start it. Oil pressure drops like a rock below idle, I wouldnt worry about that. Pulling the brake booster line will allow for airflow despite a bad IAC. If it runs nicely with the brake booster line off, i'd bet on the IAC. One of my old friends from school bought a gen 2, its beat to hell, his IAC was bad, despite my warning of cheap replacement parts, put a chinese IAC in there. What do you know, its bad again.

So now he's driving it without power assist brakes...

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I did exactly as you described and it runs smoothly! Those darn chinese sensors, never again! Will post update after putting a good Mopar sensor on

KansasRam1997 said:

I did exactly as you described and it runs smoothly! Those darn chinese sensors, never again! Will post update after putting a good Mopar sensor on

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Let us know how it goes. A lot of people come here and ask for help and never tell us if their problem ever got fixed.

Gr8bawana said:

Let us know how it goes. A lot of people come here and ask for help and never tell us if their problem ever got fixed.

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Will let ya'll know this evening. I'm at school at the moment. Thanks, I really appreciate ya'll #RamFam lol

UPDATE: put in the IAC sensor that came stock on the truck, it was still good even though I replaced it with the chinese one last November. My truck starts everytime and runs smoothly... Even feel a little more power from when I cleaned the fuel injectors.

MORAL OF THE STORY: don't but cheapo Chinese sensors. Get a good mopar one. The Chinese one lasted only about 400 miles! Spend more on quality

Good to hear you got the problem fixed.