06 Solstice. Again.
I have an intermittent check engine light. I hooked up the laptop to the car this morning and found:
- 0171 - System Too Lean (Bank 1) (Immature)
- P0507 - Idle Air Control System RPM Higher Than Expected (History) (Immature)
- P0833 - Clutch Pedal Switch B Circuit (Immature)
- P0507 - Idle Air Control System RPM Higher Than Expected
The P0833 is a new one. I'm not sure exactly what would make a clutch pedal switch "immature."
Potential vacuum leak: I can hear a steady hissing sound near the intake manifold, but it's not clear where it is coming from. Other than an occasional rough start - starts fine but stumbles and hunts for a few seconds - I don't see any indication of a vacuum leak. My boost gauge registers -20PSI vacuum at idle, which is about where it's always been.
Note that the intake manifold on this engine (Ecotec 2.4L LE5, inline 4 cylinder) has o-rings in the manifold, and doesn't use a gasket. A quick check with a ratchet indicates that it's tight, and I don't see any obvious broken or loose hoses. Still, probably worth investigating further.
I appear to need a new valve cover gasket - seeing some oil around the edges.
Last weekend, the car got pretty hot (~235F) at an autocross. I noticed some coolant smoke/steam coming from near the turbo and cat, but it's inconsistent and very slight. It's been suggested that, when I replace the valve cover gasket, I make sure that the head bolts are torqued correctly as they could have loosened up when the engine got hot.
Possibly related: I ran a compression check and found (from front of engine) 120, 120, 140, 140. Spec for this engine is closer to 150, but it's running fine.
When idling, the temp will climb from ~190F to ~203F and go back down. Doesn't really happen when driving. Water pump and thermostat were replaced a few weeks ago along with the engine.
Oh yeah - it's a "new" engine. It's possible something was overlooked during the install. (Shop installed the engine, not me this time.)
Suggestions? Please ask if I've omitted any crucial information.
Also, it idles high (around 1500 RPM) most of the time. After sitting at a light for awhile it will sometimes drop back to 1000 or so.