1997 dodge ram 1500 5.9l v8
truck runs fine most of the time but there are a few times where I go to start it and it starts up then dies right away and it takes multiple cranks to get it to actually stay on. The RPM’s shoot up to around 2500-3000k then goes right back down to 0. I replaced all the sensors around the carburetor recently. There is no check engine light and no codes are shown on my OBll.

any ideas what it could be?

 

Iac (idle air control), Or it's dirty. Remove the throttle body and thoroughly clean it.

 

And if it is an aftermarket IAC, that can cause problems as well.

 

i replaced the IAC 2 summers ago, why would it start causing problems now?

 

If it's an aftermarket IAC, they are known to randomly fail at inopportune times. Quality control is not what it used to be. As was mentioned before, clean the throttle body thoroughly, especially in the well where the IAC piston extends into. It's best to remove the throttle body for cleaning and replace the mounting gasket, too.

 

So I cleaned the throttle body and the IAC, truck seems to be doing fine now it starts fine. But I’ve noticed a pattern that every 2-3 weeks it will have trouble starting. Are there any other possibilities?

 

Did you remove the throttle body to clean it thoroughly? Also, did you replace the throttle body gasket? A stiff throttle body gasket will allow the unit to suck air and cause issues.

 

And did you reset the computer to allow it to relearn idle?

 

Yes I got new gaskets and took the throttle body off and cleaned it for about 30-40 minutes and took the IAC off and cleaned that and the port that it goes into.

 

how do I do that?