my 02 started having a nice little miss so i pulled plug wires to see if i could find the miss nuthing really stood out .so i did the doller bill trick at the tail pipe and it would suck it out my hand ...i was told this could be a bad exhaust spring,bent valve of a bad lifter...anyone ever had one do this???its a bone stock truck no modds yet...but if i half to tear into it it wont be stock long...

 

take off the valve covers and see if anything stands out.

 

yep...first thing in the mourning...

 

If nothing shows under the valve covers, I would try a leak down test. I wouldn't think its a broken spring or collapsed lifter. More than likely those would keep the exhaust valve closed, and compression would end up in the intake. I want to guess a bad valve seat or something keeping the exhaust valve open.

 

How would a broken spring keep the exahust valve closed? The spring is what closes the valve, if it is broken it will not longer close the valve.......

 

You are right on the spring. I rushes through that post. Bad info. Bad lifter or pushrod would keep the valve closed, correct?

 

Yes that is correct, if the rocker or pushrod or lifter is defective the spring will simply hold the valve closed with nothing to push against it to open it.

I wouldn't think a valve spring would be broken on a stock motor, although I have seen several of them broken on late 90's early 00's Mustang's so I guess its possible to get a defective one.

 

I had the same thing happen - ended up being a collapsed lifter. Best of luck to you!