Car misfires when hot

[ChronoGN]

I don't know why but ever since I got my turbo on, car would start misfirering whenever the coolant temperature gets around 210 degrees. The air/fuel gauge using the stock bosch O2 reading from the purple wire on the PCM reads all the way lean when this happens. What could be causing this problem?

[ChronoGN]

Oh yeah, and it has been doing this since the summmer and I've replaced the spark plugs and the wires already. Maybe its the coil? But would heat cause the coil to do this? Also, I still use 86 octane. This might be why?

[ December 20, 2005, 07:04 PM: Message edited by: ChronoGN ]

[Camaro Dom]

[img]graemlins/omg.gif[/img] [img]graemlins/omg.gif[/img] [img]graemlins/omg.gif[/img] 87 octane with a turbo?! no no NO! bad. bad chronoGN. bad!

from our own beloved modification encyclopedia:
How do I minimize the risk of detonation?
Detonation can be minimized in several ways. First, using high octane fuel is an absolute must for all supercharged cars. Octane resists burning, thus a high octane fuel will not self-ignite as easily as regular unleaded will. Second, timing retard is required on cars without intercoolers. Retarding the timing results in the spark plug firing later, which gives your crankshaft enough time to rotate into a position where the sudden very powerful explosion within the combustion chamber will rotate it in the correct direction. Third, because self-igniting fuel is caused by high cylinder temperatures, an intercooler or nitrous oxide will greatly reduce detonation.


methinks ur not misfiring but detonating. try using 92 octane and see where that gets u. whats probably happening is that ur running a low enuf boost that when the motor is cold its fine but when it heats up you're getting knock.