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Truck starts and has a really rough idle until I give it gas, and sometimes doesn't start at all

Hey Y’all, thanks for any advice!

I got a 97’ Dodge Ram 1500 5.9L that sometimes starts fine no problems at all. Sometimes it starts and runs really rough until I give it some gas and then it runs fine for the remainder of the time that it’s on. Other times it cranks and if I hold down the gas pedal it will start. Other times it won’t start up at all even with my foot on the gas. Often it happens in this order I just described in a row. 1) It starts right up fine 2) starts but runs real rough 3) cranks and doesn’t start at all. If I let it sit for a while, it seems to start this process again later.

The engine cranks strong - I recently got a new battery stronger than needed. I did change out the fuel pump some months ago (got the pump from O’Reilly) but it’s been running fine until now. It has been colder out lately than usual (below freezing), however I just tried to start it again and it’s 40F outside and it’s doing the same thing (it started up totally fine, I turned it off, I started it up again and it run rough until I gave it gas and then ran fine, I turned it off, and then I tried to start it again and it just cranked and nothing happened - all within a few minutes). I just waited an hour and it’s now starting strong and fine.

Any ideas what is going on? Thanks so much!

*Also when this does happen and I’m in the middle of nowhere mountains of snowy Colorado, are there any tricks to get it to start up so I’m not stranded?

If you just changed the battery then that is probably the cause . The Dodge V8’s from back in that era , I had a 318 if you change the battery the computer forgets all its running parameters and will run like crap (yeah it was hard even keeping it running) until it relearns the parameters . I think you need to take it out on an extended run (say 50 miles) to try and let it relearn the parameters or take it to the dealer and let them do a relearn with a scan tool . Had a Dodge van 97 and did this until it relearned the runtime parameters and I remember it actually took some time before it straightened out .

24 year old truck…anything could happen. Go to an independant mechanic because they have the tools and knowledge to diagnose your problem.

Try cleaning the Idle Air Control valve,

image

and the throttle body.

If that doesn’t fix it, the IAC valve may be faulty.

Tester

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