terrible vibrations
 

ok, yesterday after sitting in a parking lot i turned on my car and it started running very rough. it feels like it wants to bog of the line, theres a loss of power, feels like its miss firing, lower idle speed, and a very bad kinda lumpy jerk when i step on the gas even just a little bit. im thinking it migh be a bad o2 sensor or a clogged fuel filter. the car is a 86 z28 with a 305 tpi. any help would be greatly appreciated.

-Josh

Re: terrible vibrations
 

o2 sensnor should pop the check engine light. Fuel filter can do wonders.

Re: terrible vibrations
 

could it possibly be a bad distributer?

Re: terrible vibrations
 

that, bad plugs, wires.

Re: terrible vibrations
 

Check your vacuum to see if the gauge is bouncing all over the place. If it is, then rev the car to see if your car seems to smooth out at higher RPM's. If it does, pull your valve covers and look at your valve springs. Heck, it's fairly easy just to pull your valve covers and look. Might be the easiest and cheapest thing to check first anyway.

A broken valve spring will exhibit the same symptoms. My engine broke a valve spring a few weeks ago and exhibited every symptom you just mentioned.

Re: terrible vibrations
 

Oz, did it tick alot ? even warm?

Re: terrible vibrations
 

I wouldn't say that it was loud, but yes, it did tick. Noticeable at idle, not so much at speed.

Re: terrible vibrations
 

to me that just sounds a lot like a bad vacuum leak. does your cruise control work? Breaks feel normal? Check your PCV?

Re: terrible vibrations
 

The reason I wanted him to check his vacuum was because if a valve spring is broke, it'll throw off the valve timing in whatever piston it's affecting causing a massive vacuum issues. In mine, the gauge, even at higher RPM, never steadied out...it was always all over the place continually bouncing.

Re: terrible vibrations
 

sorry if this is a noob question but, how would i go aabout checking my vacuum? also there is quite a noticalbe tick at idle.

Re: terrible vibrations
 

the tick could be your exhaust manifold leaking. Loosen and retighten all of those bolts.

TO check your vacuum you need a vacuum gauge. Then pull one of your vacuume lines from your carb/TBI/TPI, connect the gauge to the hose you pulled off, plug the other side and read what the vacuum number is. If it's bouncing everywhere, you've got a leak. If it's really low, you've probably got a leak. then rev the engine, if it's still bouncing everywhere, my guess would be that you have a valve problem.

Re: terrible vibrations
 

checked the vacuum to and its holding steady at 15 hg. ill try changing the fuel filter tomarro and see if that makes a difference.

Re: terrible vibrations
 

Might check for inside of the Dist. cap being wet.

Re: terrible vibrations
 

ok ill check for that. what would it mean if it were to be wet?

Re: terrible vibrations
 

Moisture (water) had gotten into the cap. That would cause it to misfire and run bad, possible make noise. Have you washed the engine or been driving in the rain?

Re: terrible vibrations
 

i have driven in the rain but not very recently, i suppose melted snow could have cause the moisture.

Re: terrible vibrations
 

Yes, just pull the cap off and check for moisture.

Re: terrible vibrations
 

fuel filter = problem solved.
couldnt have done it without tgo, thank you