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Old 07-02-2011, 03:36 PM   #19
jhandy
Registered User
 
Join Date: Nov 2006
Location: Bastrop, TX
Posts: 705
its either Air, Fuel, Or electrical.

does it only trigger the cel on cold start up? IE: warm the car, clear the code, start the car. If no cel, then allow car to get cold. start the car, cel light immediately go on? there are different diagnostic tracks to pick of it is a cold start lean misfire vs a hot lean misfire.

If you prove to your self its not the coil pack or plug, and the wires and connection is fine, then move to fuel.

Clogged injector will trip a lean misfire on cold or hot start up. Carbon build on the intake valve from EtOH added fuel, low octane fuel use can lean misfire.

If it only does it on cold- then what could be happening is that the secondary air induction system is triggered like normal, and if it is not functioning ok, then lean mix misfire happens.

So...back to algorithm. not electrical, then pull the fuel injector and swap it with another from the other bank. If CEL comes back, then its not fuel.

look then to Air....back to the carbon on valves, clogged secondary air intake. Run several tanks of high octane gas with high quality fuel additive system to clean off the carbon. Run the car hard and hot to burn and blow off any buildup. (the next statement will come with debate)--correctly run a motor flush in the oil system. The purpose of this is to easily fix the next statement. Next look to the Cam. Remove the Cam and CAm seats. look for a clogged oil hole that supplies pressure to the lifters.

these issues can result in low fuel in relation to air- IE the reason for your lean misfireing cylinder.



And finally- if none of these steps work, then get a 1/2 inch piece of black electrical tape and .............cover the CEL light on the dash.
__________________
2002 S
Pedro rear stabilizer bar, CF strut braces, Maxspeed headers with 100 cell cats, Fabspeed cat bypass pipes, H&R springs with M030 setup, TRG rear links, EVO air intake, B&M Short shift kit, Raby IMS upgrade, Raby underdrive pulley

Last edited by jhandy; 07-02-2011 at 06:04 PM.
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