I just got my truck back on the road and am having this problem. Every time i start it, the idle goes up to 2500 sits there for a few seconds then slowly comes down to about 700. I'm sure the computer hasn't fully "learned" the truck but i still don't think it should be doing this. also when i put it in gear it wants to idle high, and when i pop it in neutral coming out of drive or reverse the rpms go up to 2000 then drop past 500. are idle relearns really this bad? mods are in sig.
Big slow mud truck with a TUNE!!!!!!
You didn't mention which mods were just done, but it sounds like you could have a vacuum leak. To verify, unplug the MAF and start the engine. If the surging stops and the idle becomes less erratic, you have a vacuum leak. Any codes being thrown?
How long has the tune been in? These don't have a specific idle learn procedure. +1 on possible vacuum leak and/or IAC problem if DWC.
Just about all the mods in my sig were done, 6.0 swap, cam, tune (2002 pcm), trans, exhaust. I did unplug the maf, started it and it did the same thing. i also double checked the tightness of my intake bolts. I'm going to swap on a stock throttle body with different sensors and spray it down with some carb cleaner and see where that gets me.
Big slow mud truck with a TUNE!!!!!!
oh yea, it's not throwing any codes yet
Big slow mud truck with a TUNE!!!!!!
Update: Today i fired it up in the morning and it idled at 1500 for a few seconds then came down to 750. went to get gas and when i started it at the gas station it did the usual climb to 2500 and come back down. this is after swapping on a different throttle body with different sensors. so i came home and unplugged the MAF, IAC, AIR, CC, took off the air filter, checked the fuel pressure and it still did the same thing. I also put a few miles on it after leaving the gas station and in drive the idle fluctuates from 1100 to 1400. I'm beginning to think there might be a problem in the tune.
Big slow mud truck with a TUNE!!!!!!
There are some tables in the tune that are "Idle Relearn" tables that need to be altered a little to help idle learn faster , at least in EFILive there are .
If done correctly idle will learn within a few miles or starts .
There is a article about cams that is titled "Start once then die" , good read .
Now what is a tune again?
Comp Cam 54-412-11 , Int:265, 212, .522 , Exh: 271, 218, .529 , LSA 114 , Longtube , CAI (Vararam) , TransGo HD2 shift kit , tuned by me with EFILive
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