P0300, P0303, P0304 after belt change
I had a squeaky belt, but once that was fixed, I traded a squeak for cylinder misfires. I'm hoping to get some help from you guys in troubleshooting. Between this forum and my mechanic, we have a good shot at figuring it out.
The initial issue was a squeaky belt. The tensioner and belt were replaced. That worked for a while, then the belt jumped my harmonic balancer. Once that was fixed, everything worked great for a few days. But on my Ultragauge, the trouble codes (in the thread title) were pending. I didn't get an actual CE light until the cylinders shut down and I run on 4 cylinders for a 30-60 seconds. That happened (and consistently happens) at interstate driving speeds, but never city driving.
My mechanic has been troubleshooting. First he replaced the coil that ran cylinders 3 and 4. That didn't fix the problem. Next, he found that the belt slipping off the balancer had damaged the crank sensor. That was replaced. Still getting misfires.
We know that this all started happening after the harmonic balancer issue was fixed, and that it only happens at highway speeds. I also noticed on the Ultragauge that the O2 sensors bottom out when the cylinders shut down. I don't know if that is cause or effect, though. I am NOT engine-savvy.
So...what should I be looking for to help troubleshoot with my mechanic?
Last edited by bishop; 01-17-2012 at 08:17 PM.