Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
Customer had head gasket replaced at another facility
P0507 and P0128 were stored
Checked for vacuum leaks with smoke machine - Found leak from valve cover gasket corner as there was no RTV on corners
Removed resealed and retested for leaks - OK
Idle is still high starts at around 950RPM when commanded is 750RPM and starts to rise as does the ignition timing advance it is about 10BTDC and then goes up to around 30 BTDC
Power steering pressure switch is operating correctly
Disconnected purge valve hose from intake - No change
Idle does not change with IAC disconnected tried using known good IAC no change
Idle speed changes with scan tool up to 1600RPM and down to about 1200 RPM
Checked in cylinder pressure as I suspected an issue with exhaust cam timing as there is not sensor on exhaust cam appears to be opening around 40 BBDC spec is 40 so I do not think it is the issue
Vehicle has not set a pending P0507 so I am going to drive it tonight and see if this is just a relearn problem
I have cleared all adaptives but it doesn't seem to have made any change
After test driving vehicle pending P0507 MAP is about 7.2"Hg baro is 30"Hg so around 22.8"Hg vacuum ignition advance is moving around 30BDTC
Any Ideas?
I found the problem! The idle stop screw had been turned out. I unplugged the IAC and turned it in so the engine was idling around 500 RPM and all seems to be well.
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