LS1LT1 Forum : LT1, LS1, Camaro, Firebird, Trans Am, Engine Tech Forums

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Silvia95 06-06-2019 09:21 PM

First off thanks for letting me join the forum and hoping to get some help with my 95 formula. The previous owner dropped in a lt1 engine from a 96 corvette and did a laundry list of mods to the engine itself. After about a month and a half of daily driving, the rpms completely dropped while accelerating and went back to normal revolutions as I naturally let off the gas upon feeling the drop in power as well as a backfire with the check engine light coming on. It does this intermittently now. It's not consistent, no trouble at all during ignition, and runs smooth even after the rpm droppage, backfire, and engine light on. Any ideas at all? Let me know if there's anymore details to be shared to help me reach a conclusion

Familiar_Enemy 06-08-2019 03:31 PM

7 Attachment(s)
When you scan the check engine light, what codes come up?

cocobolo95 06-09-2019 09:05 AM

Yes, do a code scan with an obd 1 scanner. Even though your 95 has the 16 pin aldl, like an obd 2 car has, it is still an obd 1 computer system.

Do the code scan and get back with us on what codes come up.

And welcome to the forum.

Silvia95 06-22-2019 06:40 PM

So I finally found a shop that could retrieve the codes from my lt1 swapped formula and got a "36" which points to that optispark bull that GM decided to put on said engine. Yet the techs and I are 100% sure this is what's causing the problem. Should I fork out the $1000 or so dollars to get it done?

cocobolo95 06-24-2019 08:28 AM

You could do it yourself and save the hefty labor charge. GM, Delco, & Delphi optis are around $450- $500. MSD opti about the same price. New opti & water pump seals for timing cover are inexpensive. Under $25.

95 service manual, available at following link, will have instructions on changing opti.

Shoebox site will have a pic of back of opti showing how opti drive should be installed. # 54 in component views section

You can also do a google searh using "change optispark on 95-97 lt1 engine" as your search query. There will be videos, and instructions. Step by step on & other sites.

Silvia95 06-24-2019 11:40 AM

Yea I was thinking about doing the repair myself, I've already done some research on it and kinda know what I'll be dealing with. But thank you for the info and links!

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