W es 6

iTrader: (1)

Situation: about 50% of the time when starting, the engine fluctuates horribly between 400 and 800 rpm, but then smoothes out after a few minutes.

I've replaced my Throttle Posision Sensor and my Idle Air Control Valve, I've cleaned my Throttle Body and MAF, and yet the problem continues. Any suggestions?

LS6427

iTrader: (2)

You sure the MAF is not fried? Makes sense if it is because after the engine warms up the 02 sensors take over the gig and it will idle smooth.

How about the IAT sensor in the lid? Also, MAP sensor.

Any codes?

.

W es 6

iTrader: (1)

No codes, didn't think about the IAT Sensor... what is the MAP sensor?

angel71rs

Had a similar issue with a TPI 3rg gen. Turned out to be a vacuum hose cracked in a hidden spot, sometimes leaked, sometimes didn't or not as much. My biggest clue was the pintle on the IAC screwed all the way shut trying to cut off idle air when the idle was high.

99huggerorangeZ

iTrader: (2)

pcv valve?

W es 6

iTrader: (1)

thanks for the responses, guys... I will look into all of this and keep you all posted