but not when it's hot. This is perplexing me. I can feel what seems like an ignition miss under load from startup until the car is fully warm, and then it goes away. Sometimes it doesn't do it at all. It happens under all loads, and started after I replaced the coil(bad coil) and cleaned/re-oiled my air filter. I thought it was oil on the MAF, so I've cleaned it a few times. The first couple of times it seemed to fix the problem, but now it doesn't seem to have any effect. I'm leaning towards the OPTI now, as it is the original with 151,000 miles on it. I really can't think of what else could cause this. Any ideas?

 

I have the same problem that started today. I'm going to have to clean my MAF and see if it helps. I doesn't feel like a lean miss but rather an iginition miss, hmmm..

 

I notice mine do this yesterday...

the only thing i can figure is that it is caused by bypassing the coolant from the throttlebody...

 

How did you figure that? That isn't even a logical possibility. Do any of you have access to a scanner/laptop/etc.? You need to see what the sensors are doing. Is the misfire going away when the car goes into closed loop?

 

um yeah, that was pretty much an un-eduacated guess...

only thing i could figure being the ses light did not come on and it was a mod that i did this summer...

 

Hey, at least you're thinking, which is more than I can say for some people on this site.

 

My guess would be something to do with the cold. I recently replaced almost all ignition parts including opti, and it was running fine for a while until the cold really started coming in. Stumbles anytime I accelerate but stops when it warms up. If I let the car sit for a little before driving, it doesn't happen at all.