Ya thought of that too. The prev owner changed out the lifter and did that exact thing abour a year ago, which is why he thinks the loabe is warn.

The thing is, is that I dont think if a cam was warn you would have a hit and miss MISSFIRE problem. The engine would run rough ALL THE TIME not just when it got warm or you beat on it.

Fuel is not the issue, stuck a gauge on it ran it it would start to missfire bad ( even at Idle ) would check the gauge while missfireing and it was fine 43 pds.

 

does it do it anytime it's at WOT or just high rpm range?

I imagine a worn lobe/lifter wouldn't feel much like a missfire

the possible ignition problems can be extensive
-Bad ICM
-Arching Wires
-Melted Wires
-Fouled Plug
-Cracked Ceramic on Plug
-Bad Optical Sensor
-Bad Distributor Cap
-Bad Ignition Coil
-Bad Ground
-etc

I mean there's ALOT of possible problems it could be just on the ignition side

my first step would be to run the car at night with the hood popped and look for arching

 

Agreed that I dont think its the cam either. It only does it when its gets warm. I drive 20 min to work, in the morning its cool and I have no issues at all.

on the way home its gets a little warmerMaybe 180 ( 160 Thermo ) and sometimes I get home sometimes I dont before it screws up.

You do realize I haver LTCC??

Coil per Cylinder.

Can a optical sensor malfuntion when its gets hot or warm and run OK when its cold??

Wires could be an issue but if it was it would do this ALL THE TIME.

Same with a warn lobe.

 

no didn't realize you had LTCC, so that would rule out distributor cap/rotor issues but instead diversify into a problem with any individual coil, reading the plugs will allow you to know if it is an overall condition or cylinder specific

not necessarily with wires

sometimes an arching wire will only show an issue in high rpms under a load, depending of course on the size or amount of arching will determine how much of an effect it has

optical sensor can be a hot/cold issue because with electronics any issues can be more prevelant during higher engine bay temps which can cause weak/old/failing electronics to operate more irratically due to heatsoaking

I'd say check for arching at night just to take one thing off the list of possible problems

 

Ran it around today, its throwing the front O2 Sensors, I had a friend with me who,s car did the same thing and he said front O2 sensors would be were he would start.

Also noticed something rattlin around the tranny, Maybe a flywheel or something?? Not to UP on these M6 trannys yet so maybe.

Also adjusted the driv side rockers, they seamed to be awfull tight to me, depends on how YOU adjust them. Ive always did it loosen them till them start tapping, tighten them back down slow till they stop then go 1/4 turn. Tell me if this is wrong??

 

shbox.com has multiple guides on properly setting valve lash, I always did TDC method so can't comment on the while-running-method

 

Ya Ive done it that way too, but on the engine stand, not in the car.

On a nother note.

Changed out the front 02 Sensor whith no such luck. It cant be the one after the Cat, as there is no Cat and it really isnt changing anything in the PCM. I,m at a loss.

 

did you change both o2s or just one? an o2 voltage code may be an indication of a lean/rich condition that is side specific

 

No just the one. I have Pace Setters so there in the same place on both sides. Replaced the one under the driver seat. No such luck same problem, seams to be getting worse, I,m so close to giving in and pulling the motor this weekend and seeing what I find.

There is rocker noise that is worse when its warm, and something ticking underneath when you bend down on the ground and train your ears to the underbelly its Not in the pan area though, in the tranny area, maybe the Flywheel is loose?? Dont know, Its getting warmer out and I,ll be tearing into it some more.

Hey anyone who is even remotly close to Northwest Ohio want to give me a hand with this it would be greatly appretiated.

 

Pulled motor apart, as was expected the NO 7 EXh lifter was fubared. Havent pulled the cam yet but sure its fubared too.

There were others in defferent locations on both sides of motor that were showing pits and hard scratchs.