anyone have any ideas?

[nickhinton]

hey guys i just joined this site a few weeks back, and Its been a ton of help so far. I recently started running into an issue with my 94 z28. I bought the car with 190k on the body and a supposedly rebuilt motor. It ran strong for a few months after i bought it and its recently started running rough under mild/moderate acceleration off the line or when going down the road under load like when its in 4th od and tcc is locked it was start bucking and backfiring and surging unless you step on it enough for it to kickdown and then it clears up. Since ive owned the car ive installed pacesetter LT's deleted air and egr ( car was running fine for about 3 months after delete without these tuned out) New bosh 02 sensors, ngk tr55 plugs, new wires, poly trans mount and motor mounts, and an oil cooler delete. I noticed this starting after back to the bricks the car got hot but didnt overheat and it started having this issue. When its started on a cold morning it runs fine in all conditions its only when it reaches operating temp. So i installed a 160 thermostat and manual fan switches and it helped by keeping the temps down but as soon as it starts to heat soak under the hod i start with the surging backfiring problems. Anyone got any ideas or know of any decent places around flint to have an obd1 scanned at? I havent been able to get my aldl cable yet to scan myself and i think it would help pinpoint me in the right direction. Heres a video, kind of crap quality but you can hear it kind of hesitate and bog and the second time you can hear me put it to the floor and it spits for a second and then takes off. Thanks in advance for any help guys

[Fox Slaughter]

Signs of a bad opti to me.

If its doing it when its heat soaked try spacing the ICM.

[nickhinton]

I forgot to mention I put an msd coil on it when i bought it too. I tested the map sensor, and icm the other day but not to say the test was 100% correct. Ill try and throw a couple washers in it and see if it makes a diference at all, im starting to think its time to put it up for the season lol. This being my first f body i dont have any expeirience with the optispark on. Is that something that would give issues only when hot or would they be noticeable symptoms all the time if that was starting to fail?

[Fox Slaughter]

The opti is strange. It can range on bunch of problems. I mean check all the easy stuff first. I posted a thread in the How To section on diagnose a Opti.

[nickhinton]

yeah thats what ive seen browsing around, im thinking its time to finally invest in the scan cable too, and start saving eenies for some new parts in the spring.

[Fox Slaughter]

Do you have any SES lights on?

[1BADAIR]

check the plug wires

[Fox Slaughter]

Yupp do you have headers?
If you do burning plug wires is a very common problem.

[nickhinton]

no ses light even when it starts running rough, i did pull a couple plugs about a week back and they were kinda fluffy black so its running rich (which i partially relate to no tune). im beginning to think switching to the tr55's wasnt a great idea, i had double platinum factory delcos in it and the other forum im on everyone raved about the copper tr55's. i think i might try switching back to the old plugs too

[Fox Slaughter]

I only run NGK copper.

Also I noticed you do have headers, when its idling can you hear a clicking with the hood popped? Its the sound of a plug wire arching to a header. If you rev it up the sound will get faster.

Also I had a MSD coil and returned that piece of crap.
I had a MSD opti when I bought the car test drove it 3 times, 2nd day I had it the opti died.
The only thing on my car that is MSD is the harness to connect my Mallory 685.

[nickhinton]

I havent been underneath the car to check yet but after i insatalled my headers i did burn my set of wires, so i swapped them out for a new set and replaced them again. The only spot i can see thats close is cylinder 8 on the pass side, the boot going onto the plug is only about an 1/8 of an inch away from the primary tube. no clicking and i kinda looked around at night and didnt see an arching but thats not to say im missing something.

[Fox Slaughter]

If you have a multimeter you can ohm out the wires.

[nickhinton]

ive finally got a day off tomorrow, ill go get it and bring it to the garage and see what i find. I appreciate all the responses so far guys, awesome looking cars by the way

[Fox Slaughter]

Youre from Flint. There is no work in Flint. Now I know youre lying!

[nickhinton]

hahaha, well grand blanc, but ive got one more semester of school before i can start making halfway decent money and give the car the attention it deserves, a college budget really cramps your style when you wanna buy goodies