my car is a 95 z28 engine is stock only mods are pacestter LTs and k&n CAI.
during my drive home from work, i started getting a very violent engine shake and the car has no power. i had to give at least half throttle to keep it from stalling at a light. car is not throwing an SES or anything but i have not been able to get it scanned. it was fine for about 90% of the drive, luckily this didnt start till i was only a few miles from home. it was raing, but i have never had a problem with rain before.

 

Welcome to the wonderfrul world of the Optispark.

 

you arnt running out of gas are you?

Check your hoses and water pump to maybe one is leaking onto your opti

 

Maybe a huge vaccum leak? When was the last time you had a tune up?

 

bad icm maby

 

was low on gas , but not any lower than i had run it before.
just did pugs a few weeks ago when i did my LTs. havent done wires yet, but it has been running fine.

i let it sit for about an hour and a half went out and took it arounf the block and it ran fine. went to get gas about 15 min later and it started acting up again. seems like it only happens at operating temp. i shut the car off coming to a stop sighn and stated it back up and it was fine again for a minute or two. also seems a little sporadic, will stuble and studder then take off the studder again

ia m also thinking i broke a pass. side motor mount because the flat spot on the pacestter ypipe is now sitting against the floor pan when i had a half inch gap a couple of days ago. i havent been hard on it so i know i didnt twist the frame.

 

ill bet $20 you burnt a wire or 2.

You allw ways see it here right after people do LT's 99% of the time

 

the out side of the wires appear fine. that was the first thing i checked

 

Get the car in a dark place and start it and look under the hood for arching wires.

Follow each wire with your eyes, you can also get a spray bottle of water to help show the arching.

Their are several other things that it could be but my money is on the wires.

Maybe you can take to a auto parts store that will scan it for free and see if their are any stored codes (SES light doesnt have to be on for a code to be their)

 

egr valve feels like it is stuck open. could this be the problem? i tried pushing the plunger up and it only moves maybe an eight of an inch and then bottoms out.

 

I second the wires. It happened to me, same symtoms. I had burnt one and it didnt even really show it, I had to pull the wire and bend ti to show where it burned through. It happened about 2 weeks after my LT install.

 

i would think though if it was a burnt wire it would do this all the time not just when it warms up

 

I wouldnt think so but dont know for sure, i mean how could it cause your car to miss as bad as it is?

Check the wires first like i said then move to other things.

And BTW when you do get new wires go with the OTVC (over the valve cover) set up.

 

well i just went out and checked for arcing in the dark and saw nothing. im taking tommorrow off work to try and fix this. ill post up what i find if i find it

 

Did you wait for the car to heat up and start missing?

A few other things to check

o2 sensors (you can unplug them and force the car to run in open loop and see if the problem goes away.)

MAF (mass air filter) do the same as above, unplugg it and see the problem goes away.

Check for any burnt wires (not just the plug wires) near the Lt's

A heat related isue might be the ICM (ignition controll moduel) maybe try tempararly taken it off the head (so it doesnt heat up) and see if that helps

But i would still put my $$$ on plug wires, you couldnt count howmany people burt wires after a LT install. If you are going to get new wires anyways might as well do that first before you start throwing other parts at it to try and fix it.