Hey guys I have a weird issue on my car and it goes like this

Cold start is fine and after a few minutes when the car is warmed up it will rev itself to 3k rpm so at this point I said maybe if I drive it, it will go back to normal but getting off gear it will drop the rpm but sputter while accelerating and once I go back to neutral it will rev itself to 4k.


I thought it was my battery but I replaced it and still does it. Then I thought it was my double din taking too much charge so I took that out, still does the same; then I replaced the positive terminal and still does it. I dont think its a boost leak or anything because a week ago it drove fine


Thanks guy for any input

 

This is a long shot, as I've never seen the idle go out that much, but perhaps your BISS and idle re-learn are way out of wack. Could be a failing IACV as well.

 

It was going to go past 4k but at that point I didnt want to hurt the motor so I shut her off; this happened after 1 week of driving fine, the battery died and I jumped it, after awhile revs jumped so I turned it off looked at the bay and saw a swollen battery, I thought that was the issue but it still does it, doesn't happen immediately only when the car warms up a bit

 

Not sure if it helps but I had something a little bit similar. All my lights dimmed and the engine revs would bounce between normal and 3K while in neutral after a somewhat long drive. It turned out that the voltage regulator wasn't doing its job and it would be over the threshold needed to charge the battery. It would go back to normal after reducing the load like turning off my radio and stuff. I had to swap out the alternator for a new one.

 

try clean your iac valve and try unplug any sort of volt stabilizer or anything thats attached to ur battery, also unplug any unnecessary wiring u can see.

 

My car did this when I pulled my valve cover make sure your throttle cable is clipped in right if it's not it will hold the throttle plate open and cause it to rev up mine was hanging at like 2500rpm lol threw me off for like a half hour till I realized it

 

might need a re tune

 

start with cleaning your IACV

 

Hey guys quick update,


Cold starts are fine now and the car does not rev itself up when its warm, now it just shuts off when its warm; iacv is fine and the battery is also fine now

 

Figured it out bad connection to the ecu

 

Check for boost leaks and test your ISC.