Ruff idling comes and goes...5.2L

it all started when I couldn't keep my truck started. It would start right up but as soon as you give it gas it would die right out, then wouldn't start unit I let it sit over night. Thought it was the crank position sensor, replaced with OEM but didn't fix it. after further diag decided to check the IAC valve and noticed it was all gunked up. cleaned it up and noticed a little difference, would still die with gas but not right away and it would start right back up. So I replaced the IAC valve with an A/M brand from NAPA. Runs and stays running. took it out for a ride around the block a couple of times and seemed fine. after letting sit for about an hr took it to the store, on the way there it started to loose power a little bit when I would give it gas (sounded like it wanted to stall, and made popping sounds). now every time I started it after about 2 mins it sounds like it wants to die out (makes almost a whistling sound) until I give it some gas then its sounds fine. Then occasionally it will try to stall out but doesn't. Any ideas?

Welcome to RF

Have you checked the fuel psi at the rail? should be 49. Thats where I would start.

It sounds to me like it may be the cam sensor as well. If you decide to replace it make sure you go with a mopar sensor, as others are prone to failure.


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Merc225hp thank you. I checked the fuel psi before I replaced the IAC vale and it was at 49. maybe ill have to check it again.

Magsport I will definitely check out the cam sensor, thank you. with something like that I would only go Mopar. im actually considering returning the aftermarket IAC valve for a Mopar one.

Next thing for me is a Mopar IAC but I would be picking up a CKPS at the same time.
CKPS= Crankshaft position sensor this is not the one under the dizzy cap Cam sensor. CKPS is a pita to change out and will do some very funky things as it goes down, warm or hot and it might fail, cold it works fine. CKPS in on the back of the motor pass side BEHIND the head yeah real fun to get to.

Merc225hp said:

Next thing for me is a Mopar IAC but I would be picking up a CKPS at the same time.
CKPS= Crankshaft position sensor this is not the one under the dizzy cap Cam sensor. CKPS is a pita to change out and will do some very funky things as it goes down, warm or hot and it might fail, cold it works fine. CKPS in on the back of the motor pass side BEHIND the head yeah real fun to get to.

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yeah the CKPS is a real pain to change out, the first bolt was kind of easy to get out, but the second one I had to call a buddy with skinnier arms to crawl under the truck and go from below. im just hoping the cam sensor isn't as hard to change

Cam sensor is easy, remove the dizzy cap, the rotor button and there is the cam sensor, nothing hold it down just lift it out and replace, make sure you get the new one sitting in the dizzy right. Make sure you diss conn the batt before doing this job.

That's awesome. thank you very much for the info. sounds easy enough to change

I would suggest checking your MAP and TPS sensors aswell