Need help! Multiple cylinder misfire

[Gashaw40]

My truck is running like crap , says it has multiple cylinder misfire and o2 1/2 circuit high. It has no power now and the whole front end shakes going down the road. it has an exhaust leak at the headers. It's running rich and backfires too. What could cause this . I tried replacing spark plugs and new plug wires. Could the o2 sensor be causing the rest of the problem or the exhaust leak or both. I have ordered an o2 simulater from the fastman.

 

[dodge dude94]

Have you replaced your plenum and done a tune up recently? Checked your cat? Replaced your O2 sensors lately?


All stuff you gotta look at.

 

[wingnut]

Multiple cylinder misfire was a bad fuel-pump/low-pressure in my truck. Go to Autozone and rent their fuel pressure tester kit. Verify 45-50 psi. A truck will idle with as low as 18psi, but will run like ****. This would also give bad O2 readings.

 

[dabranco]

I had the same problem. Did a complete tune up still have a miss but it was better then cylinder 1-7 misfiring