running rough!!

[Azrael]

Which two pushrods did you mix up? I wonder if a valve was slightly bent from that and is now sticking in it's guide.

[Rootie524]

nah i fixed all that. it was indeed bent but it got replaced. i had a exhaust rod on intake valve iirc. basically the longer rod on the one that required the shorter one..needless to say that didnt end well. broken rocker, and bent valve. replaced both, rod was fine..then went on my merry way.

but u raise a good point now..but somehow..idk how..but for some reason a valve might be stuck in the guide. which is kind of the same thing has a lifter being stuck as well. but took the front valve cover off and all was running great up there. so if there is a problem, it's in the back. but the more i think about it, the more it sounds like a valve issue. but this could seriously be like 50 things..so its all guess work right now.

[bszopi]

Was the original bent valve on the front or back?

[Rootie524]

back

[bszopi]

So, then if it has to do with the valve in question, you need to check the back head. You should be able to relocate the ICM temporarily and still get the engine to run, with the back valve cover off. Or, if anything, take the ICM off, along with the back valve cover, and have some one crank the engine over while you watch (and listen to) the valves. Its not going to run with the ICM disconnected, but it will crank over, which will at least help somewhat in diagnostics.

[Rootie524]

i was thinking of just doing a compression test on the back head because then i wouldnt need to remove the alt to remove the valve cover. but after thinking about it, it's probably going to be alot easier just to remove the alt and valve cover than trying to do a compression test in such a small hard to reach area.

so ill be doing that today..if all the valves seem to be moving properly..i guess ill check fuel then. because ignition is fine, air is fine (unless the intake valve is stuck), so then next is fuel i guess. all sensors seem to be fine. but ill let you all know how it goes today.

[robertisaar]

if the malibu is anything like the MC for a comp test, yeah it's a bit of a pain. like as bad as changing plugs.

[Rootie524]

yeah it is..a big PITA..and i just recently changed my plugs so i dont feel like going through all that again. i much rather remove the coil pack and alt..

[Rootie524]

Front valve cover removed: All valves working properly
Rear valve cover removed: All valves working properly
new spark plugs
new ignition wires
new coil pack w/ ICM
i thought it might be all the ignition timing i have..so i put in my original PCM..problem persisted.
thought it might be a dirty intake filter, so i unhooked my AI right before the MAF..problem persisted (throttle body also looks dandy)

So..all valves are fine, spark is fine, the PCM and the dyno tuning is fine, air induction seems to be fine, shook alot of wires and sensors and nothing changed.

So this is either something serious..or something im completely overlooking. and all the computer says is random/multiple cylinder misfire. There is one more thing i can easily try which would be the MAF..ill change that tomorrow. It would make sense because the car kinda struggles to stay up sometimes and it could be because of a faulty MAF sensor and that might be causing this huge headache. and if it's not that i guess it's still possible one of more of my injectors is broke? does that seem logical?

and i was thinking something as simple as fuses..but if it were a fuse i doubt it'd work sometimes and then not work. if a fuse is gone..im assuming it's gone for good.

dare i say i could have spun a rod bearing? i dont know much about that but is it possible its spinning so much that sometimes its good and other times its not? because it runs horribly rough and im guessing a car with a spun bearing would. let me know what you think. it seems to be getting worse in the sense that there is barely any good running time..now it seems to be bad all the time.

[bszopi]

It could still be something electrical. In my old Alero, we had an issue with starting intermittently. After the shop had it for ~1 week, starting it 4-5 times a day, it finally did it for them. They traced it down to a short INSIDE the fuse block. How they ever found it still boggles my mind. Replaced the fuse block and all was well. So, trying to track down intermittent faults, especially electrical, may best be left to a shop who has all the tools and know-how.

[mickaz]

the more i hear it, the more it looks like a prob I had before. One of my valve was leaking throught the exhaust. it was enough to get a blinking CEL. try a compression test and go on from there.

[Rootie524]

what do you mean? the valve wasnt seating right or something?

[86FieroSEv6]

If you have enough guide and or stem wear, some pretty strange things can happen. Or, carbon buildup for that matter.

[Rootie524]

would a compression test figure out valve guide wear? and should i run some sea foam through it or something.

im kinda hoping its just as simple as getting a new MAF..so when i try that tomorrow and it doesnt work ill just suck it up and do a compression test and hopefully get an idea whats going on. im slowly eliminating possibilities.

[mickaz]

well if one of your valve doesn't seat you will know from the comression test. do you get a random misfire code OR a specific misfire to a cylinder? im pretty sure its a valve that doesn't seat or something along those lines.

by the way when you have a check engine with a misfire or something like that ALWAYS do a compression test first will save you lots of money! trust me!