LT1-LT4 Modifications - 95 LT1 acting up

the car: 1995 LT1 Trans am, 106k miles (had it since 99k miles), 6 speed, has a Moroso CAI, Granatelli MAF sensor, Hooker super compr LTs and 4.10 gears


the problem: tha car used to run fine with this bolt ons, out of no where started having little ramdom detonations when its at idle (they just sound out of place), when the car runs from idle till aprox 1700 rpms it starts misfiring badly and knocking, sounds like the timing is too advance or running lean but I'm not sure. I scanned it today and it gave me a TPS low voltage, but I replaced the sensor and nothing happened...

my guess: a couple of months ago I was at the track and shifted from 2nd to 1st by mistake, as soon as I felt the wrong shift I pressed the cluch and the car ran fine, could the timing chain streched from this? or could this have something to do with the EGR being eliminated?

Sounds like a bad plug/plug wire or an ign coil. It could also be a clogged fuel filter. It could also be the MAF and TB needs cleaning or some dirty injectors.

Sounds like a bad plug/plug wire or an ign coil. It could also be a clogged fuel filter. It could also be the MAF and TB needs cleaning or some dirty injectors.

I cleaned the MAF and air filter yesterday, tomorrow I'm changing the fuel filter and checking the plugs and cleaning the TB, ignition coil is about 10 months old, and just checked the plug wires and they don't arc anywhere, am I overthinking this ? thinking that it could be the timing chain?

opti...

opti...

:bang: i really hope is not that, how do I make sure? and just in case other than MSD wich other opti is good?

It'll be the opti before the timing chain. With the miles on it the timing chain should be fine. The best opti to go with IMO is a replacement AC Delco others have had luck with cheaper ones

Just because the plug wires don't arc doesn't mean they are making good contact with the plugs, and looking at the plugs won't tell you if they have a bad center electrode. If either of them haven't been replaced for a while it's a good I idea to replace them. Also check out the thread below, bad O2 sensors will cause a misfire.

http://www.ls1tech.com/forums/generation-iii-external-engine/1334779-misfire-rough-running-after-rain.html

I'll scan it again tomorrow and double check on those O2 sensors, does the EGR advances the timing? cuz I just talked to my dad and my brothers car(94 T/A) did the same thing a couple of months ago, still hasn't figure it out

Not having the EGR will not change a thing

cool, I've heard that it mess with the timing but I wasn't sure

Yah it sounds like you need to check your opti. Change those plugs and wires while your in there if they are old.

new spark plug wires, plugs looked ok, TPS ajusted to .65 - 4.5 vdc, TB cleaned, new fuel filter, all of the gounds on the engine bay are cleaned and have good conections, plus I added an extra ground, and the car still does the same sh!t, won't do it from idle but if I step on the gas from crousing it will stumble and shake and knock, what's the next step? injectors? fuel presure reg? or straight opti?

It could be the opti, o2s or even a dirty MAF. Does it act the same way at WOT

I'm no expert but my experience with opti's is they start fuckin up at high rpm's and go down hill from there...but that's only one mans opinion...

Clean your maf...

if it is on the correct gear it does not, for example if I'm doing 45 in 6th gear and I press on the gas it will stumble and fvck up, but if Im doing 45 on 4th gear and press on the gas it wont do it, I really don't feel like spending 475 bucks for the MSD opti and then find out it wasn't that

im going to have to try somebody else's maf, cuz I cleaned mine and it looks good, wasn't really that dirty

best thing to do is plugs wires coil and opti all at the same time kill a few birds with one stone thats how i did mine, Everyone makes out like the opti is hard to replace its not bad at all. As mentiond above use a ac delco opti

heard not so good things about the MSD opti, best bet is going with ACDelco.

and it's the only thing you've been avoiding... yet still have a problem... lol

good luck. and yeah the only thing with opti is lining it up right when installed. (know someone who had theres plugged in wrong somehow)

guess I go that direction this week, see if I can get it track ready for friday, btw I noticed today that the weather was cool about 65 degrees and it ran fine, after the car warmed up and outside temp rised to 75 it started doing it again, but anyways I'll get that AC delco opti

so I just installed a fuel pressure gauge on the car, at idle its reading 33 psi and when I rev the engine its close to 40 psi, if I disconect the vacuum hose from the regulator its jumps to 40 psi, could that have anything to do with my problem??? should that be a bad pump or a bad regulator??