One of the few times a new vehicle had me consider calling the hook was a K&N air filter screwing up the engine. All of a sudden after eating lunch one day the engine would start and stall on a 2002 Chevy pickup with the 5.3L V8. I could rev it up and it would stay running, but, the second I took my foot out of it to shift it stalled. Did this 4-5 times and then stayed running. Then randomly would do this for a month. Dealer couldn't find anything.
I was sitting watching the tach after one episode and noticed it was at 450 RPM. I pulled the IAC motor out and found a dust build up that was choking the idle air off, yet, the "touch" part of the valve had kept the dust off. So the ECM would do a "touch" to learn the valve position, but, couldn't measure the dirt and PCV vent crud build up that was choking off the air. I cleaned the IAC and problem went away. Next day I tossed the K&N and put a paper filter back in. Never had the stalling problem with it again.
Pictured is a 2002 GMC Yukon that had one of these K&N gravel screens. Note the clear "touch" area of the pintle. The engine ate this kind of dust from using a K&N. Dusting the rings ... requires an engine rebuild to get this grit embedded in the rings, piston, and cylinder walls out of an engine. Service air filter every 50K-100K miles as you see in the pic is a bad joke.
I was sitting watching the tach after one episode and noticed it was at 450 RPM. I pulled the IAC motor out and found a dust build up that was choking the idle air off, yet, the "touch" part of the valve had kept the dust off. So the ECM would do a "touch" to learn the valve position, but, couldn't measure the dirt and PCV vent crud build up that was choking off the air. I cleaned the IAC and problem went away. Next day I tossed the K&N and put a paper filter back in. Never had the stalling problem with it again.
Pictured is a 2002 GMC Yukon that had one of these K&N gravel screens. Note the clear "touch" area of the pintle. The engine ate this kind of dust from using a K&N. Dusting the rings ... requires an engine rebuild to get this grit embedded in the rings, piston, and cylinder walls out of an engine. Service air filter every 50K-100K miles as you see in the pic is a bad joke.