Gold Phoenix

iTrader: (1)

I have a all stock motor that runs rough from idle to 2000rpm. And just two days ago, the SES light was flashing at me. I hooked up autotap and DTC said Cylinder Misfire Detected. I looked at the misfire history of all 8 cylinders and #4 & #5 had alot. Now, I had two misshifts from 3rd back to 2nd about a year apart. After the 2nd overrev, the misfire code came on. I changed the pushrods to chromemoly ones and the code ceased, but the motor still operated rough. I also have new plugs and wires. Now could it be the valve springs and/or lifters? What about the valves? Could they be bent? Don't get me wrong, the car still pulls hard and the gas mileage seems unaffected. I need some ideas to figure out this problem.

wrencher

iTrader: (2)

I would have to say you need to do compression testing.
Then if any cylinders are found to be low,like #4 & #5, do a leak down test.
This can confirm a suspected bent valve.

Gold Phoenix

iTrader: (1)

Well, thanks anyway. I came into some extra cash and I am just going to change the lifter and springs. While I have the heads off, I will look at the valves and do some mild porting of the intake and exhaust.