My mechanic and I cant figure this one out... My Blazer is misfiring on cylinder 1 but only in idle. He adjusted my timing and now its on, on another pick-up having the same problem he out a new EGR valve on and that didnt fix it either. Any of you guys have a suggestion. The only reason I care is because its giving me absolute terrible mileage, and also its running really rich! If I sit in idle for like 5 - 10 mins there is just a black puddle, and when I floor it while driving...I have a lead foot...I have a tendency to do that...I can just see a cloud of black, I can blow more black than some of my diesel friends! I dont know if this is related or not but your help is greatly appreciated and am open to any suggestions you guys think will help!

Thanks, Ethan!

 

How is the O2 and map sensor response/readings?

How did he determine that the misfire is cylinder #1? Has the compression been checked?

 

I cant even find the O2 sensor on there, haven't checked the map either, but those are the first two I thought of too and he used a reader that hooks onto the plug wire and reads it some how, he just told me it was misfiring on 1. I wasn't at the shop when he did it, so not 100% sure. I was going to change the O2 sensor but cant find it. And no, the compression has not been checked, the motor is almost shot so I dont wanna throw too much into it, just has to last me until June.