Help! I have a 2000 z28 with rough running LS1. I went to pick my son up at Karate tonight. Driving out of the lot the car started running bad. Barely made it home. Rough idle and smoke coming out of the air lid once I shut it off. Oil looks fine, no water. Coolant looks fine. Battery was putting out 12.3 vdc. Car runs but has a chugging sound at idle but revs up. My guess either a bad cat, bad 02 sensor or a battery making things freak out! I need some help here guy's

 

Did you have to give it a lot of throttle to get it to move? My moms bonneville started running very rough and would barely move under full throttle. It turned out to be the alternator. The rough idle has happened to it twice and the alternator was the cause of it both times. Check your fuel filter too. It could be clogged up just enough to make it run rough at idle. Hope this helps.

 

I removed the MAF and belows. When I tilted the throttle plate open I could see what looks like oil in the intake. WTF! Oil level looks fine. I was doing about 20 mph thru a parking lot when this started. Anyone what to guess or should a diagnostic test tell?
Should I pull the plugs and look for somthing like oil on a plug?

 

Looks like my PCV valve failed. I am going to get the GM #12572717 I think this is the new style.

 

PCV did not fix rough idle. Did a compression test 195 -200 on all cyl but #7. I found #7 intake spring broke and push rod bent!!!
Ran comp test after removing rocker on #7 and got 200 psi with no leak down. Anyone have such a problem? Should I pull the rest of the rockers all other cyl inders check good with no leak down. Man, this failure occured at 20 mph and 1500 rpm.
The spring must have been going. I need some advice here guy's

 

dude this same thing happened to me...only i snapped a pushrod in half. It seemed like a major problem, but if it is only a pushrod, its a cheap fix. I got mine fixed for 180 labor and all.

Some a$$hole mechanic tried to tell me that my #6 was shot and I needed to replace the whole engine and after labor and all i was looking at 11,000 dollars. I told him to suck somethin' and i took it to this other guy and it was only 180. hope this was some help. Good luck!!!