Hello I have 2 dodges that I'm having a problem with. 1st is a 2000 dodge ram1500 4x4 with a 5.2. What is going on is when cold or right after a warm start up it runs real bad with hesitating and backfiring no power. This lasts for anywere from 1 to 5 min. After that it clears up and runs great. If I stop at a store run in and grab something come out and start it up it does the samething for the same amount of time? It has no codes, I have read the data stream and all the temps seem fine (it's not reading like -50 or anything like that) The iac motor was bad so that was replaced along with the tps and all adaptives were reset. Everything was also cleaned T body and iac port. I'm having the same problem with a 98 durango with the same motor. Any help would be great thx Jim

 

Possible O2 sensor going bad. Is it right after warm up or right on first key on cold engine?

 

Thats the wierd thing is it will do it 1st thing in the am but will do it right after driving to say the store and shuting it down for less than a min and refire it will be just like back to square 1. I read the data stream for the o2's and they seam to be reading about the same give or take a couple points.

I had a problem with a ram before with missfires and hesitating that turned out to be an o2 but it also had a code for it and u could see on the data stream it was not reading right.

 

When it first starts its fine than the Idle air control module opens up wide, increases the vacume and sounds like a jet taking off. after it warms up competely goes back to normal. Took a code off and got the following "System too rich Bank 1 (Code 172). Thinking of replacing the O2 sensor. Other suggestions welcomed. Thank you.

 

Replace the 02 sensor then! Sounds like you have a California emissions vehicle. I'm only guessing since you have no info about your truck and you jacked another members thread!

 

LOL/ouch. that was bit harsh. funny as hell, but harsh.

 

Well what the heck! lol

 

try replacing pre cat O2 sensor. I had the exact same problem on my 2000 2500 and replacing the pre cat O2 fixed it.

 

Thank you for the advice. much appreciated.

 

Well I have replaced both o2's, tps, iac, and the map sensors and still no good I have not replaced with new but from a good running truck. Fuel pressure is fine at just below 50psi. It's wierd cause it will run great right after u drive for less than a 1/4 mile but u shut it down and restart it will do the same thing all over again. It backfires spits and farts no power unless I floor it.