I have a 94 Trans Am with a LT1 350 and I am having issues with the engine. I had it in storage for the winter and when I pulled it out it did not want to keep running. I changed plugs, wires,oil, oil filter, fuel filter. So now the car idles fine but when in neutral and throttle pushed it backfires a little and when in drive and when trying to accelerate the car compltetly falls on its face and becomes gutless. It has almost a stutter to it. I can't determine what to try and replace or to just let a mechanic make that decision. Any help would be greatly appreciated.
Thanks

 

well, you'd probably be best to go to a 4th gen forum or LT1/LS1 forum.

But, since I also own a 4th gen LT1 what you describe is not uncommon

did it behave that way prior to storage?

what fuel stabilizer did you use in the gas and how did you prepare the vehicle for its winter slumber?

do you have access to a laptop computer?

If so

www.aldlcable.com and get a cable

then you can at least log data and see what's going on

does it do this both cold and warm aka open and closed loop?

If so, then either you miswried the plugs, didn't seat the wires all the way, broke an insulator on one of the plugs when they dropped or ......... Mr Opti wants to be replaced

If it runs great when cold (open loop) but lousy when hot, then that cable will help but you probably have a bad o2

good luck

 

When the car went away in storage it ran perfectly fine but all I did for winterization was throw a little sta-bil in the gas tank.

So far I have put a seafoam and lucas injector cleaner addative in the fuel tank.

I'll have to try to use the computer but it seems to do it both cold and warm engine.

Thanks for the input and is there anyway to check if the opti is bad?

 

For the stabil, did you add it to a full tank or add it and then fill the tank? I had this problem with another car of mine (not an Fbody) that had similar symptoms. Bad fuel will cause what you're describing. I'd say throw some heat in it to help with water, then fill run the car and replace the gas in it. Should clear up as the new gas filters in. however, these cars like to be driven so whenthey are parked, things, especially electronics tend to go bad. So new gas may not be the fix.

 

Don't need to datalog - this is OBD2 system - any auto parts store can pull codes for you for free.

You said you did plugs and wires. Are we being honest here? Or did you just state that so we wouldn't say do plugs and wires? Because no one with an LT1 wants to hear about plugs and wires (I know, I have a 1997 LT1). Because plugs and wires on an LT1 are very very difficult to do. I'm not trying to be a jerk here, I'd tell a fib too just to see if anyone had any ideas other than plugs/wires - because I know what a PITA they are on a LT1 and I'd want to try ANYTHING else first!

If you have backfiring issues, and stumbling, then you have an ignition issue - and everyone is going to tell you 1 of 3 things ... 1) plugs, 2) wires, 3) optispark. If you did 1 & 2 correctly, then you need to look at the optispark.

Only other thing might be MAF - can try MAF cleaner and TB cleaner - but my money's on plugs/wires/optispark.

 

newb, OBD2 didn't come to the 4th gens until 1996.

the 95's have an OBD2 connector but OBD1 computer. You can get an Actron 9145 scanner and an OBD1 connector and power adaptor and it reads OBD1. On my 95, the Actron just plugs into the connector and reads my OBD1 computer.

The OP has a 94 so that's an OBD1 connector so www.aldlcable.com is the least expensive path. I have both the Actron 9145 as well as the cable which is needed for flashing the computer.

and long tubes make plug changing easy. If you suspect the MAF, simply disconnect it and the car will go into speed density mode, run crazy rich but you can rule it out real quickly.

the LT1 can be intimidating at first but once you get it and its reverse cooling figured out, they are a heck of an engine for old technology and the low end torque is awesome.

 

I knew that!

I have some dental surgery coming in April - maybe they can screw my head back on tight while I'm under!

 

it's easy to lump them all together. The 4th gens just happen to cross over on 2 sides of 2 significant changes

OBD2 in 96 and then the LS1 in 98.

when you look at a 93-97 you can't tell from the outside if it's OBD1 or OBD2.

Then they have the 93 which was unique to itself with non heated O2's. 93 and 94 used the non vented spline drive optispark, 95 began with the vented spline drive optispark and then 96, 97 had OBD2 and a crank position sensor

In 5 model years there are 4 major differences!!! Then they toss the LS1 into the mix starting in 98

all of those differences

 

Hey thanks you all for the help. I guess it must have been the bad gas and gummed up injectors. I seem to have run enough gas through it to help clean it out. Sorry about joining the wrong generation and yes I did actually change the plugs and wires and yes it did suck. Thanks again for all the help!