transam35

i have a 96 lt1 and i think i have a bad opti. SYMPTOMS: when the car is cold the car runs just fine,well for like the first minute it is on then i get a real bad miss. from idle all the way up to 3000rpm(sometimes up to 2500rpm)it varys. when the car is warmed up it missis only when i put more than 25% throttle or more in at any rpm. so basicaly when i stop and go i have to slip the clutch almost everytime. Example say iam at 60mph in the freeway in fourth say at 3500 rpm. and i give it anymore than 30% throttle it just feels like the car misses. the car has never turned of on me or anything but i always have to go threw all my gears very slow.
does any one think this might be a bad opti? or coil? any help would be great help to me. THANKS FOR YOUR TIME

Guest47904

Certainly could be opti problems. But it could be a lot of other things also. First, how many miles on the car? What's type of maintenance has been done? Has any ignition components been replaced? Remember plugs, wires, cap, rotor, O2's and coil are all considered tune up items. Do you have an SES? Do you have any DTC's? How's your air filter? A bad filter will cause it to run rich and foul plugs and causes an otherwise good engine to run poorly.

Taken a step further, the rich burning engine now destroys the O2's or plugs up/wipes out the cat. But those problems on an OBDII would throw DTC's after a while.

I would look very closely at the ignition components and replace them if they haven't been in a while.

Got another opinion on the opti but will reserve it for later after your repsonse.

transam35

the filter is new. ive done all the oils in the car engine oil. tranny oil, rear end oil. but no plugs wires or coil since ive had it. i just bought the car about 2 months ago and it did have 113,000 miles on it. guess i shouldent of ran real hard till all the maintence was done. car ran real strong when i first got it.
I was running 9.1 in the eighth all day. but a soon as i ran in the 1/4 things went to like 9.7 on the eighth then 14.6 in the quarter with the car running with lost power.

Guest47904

Does your SES come on during the diagnostic light check when you first turn the key on? Because if you have a miss as bad as you claim, the OBDII system should be setting a misfire code and will eventually set the SES when the misfire counts get high enough. The very first thing you should do is have it scanned for DTC,s. Then depending on what you find, will determine your next course of action.

Do you hear what I call a shhh shhh sound? Some think it sounds more like a clicking? It's a good possibility that your track runs could have pushed a marginally tight plug loose causing a misfire. But still you would set DTC's for that and eventually set an SES.

Do a complete and thorough tune up.

As far as the opti goes. It is always a good idea to change out the entire unit. The bearing goes bad among other internal problems. There I said it. BUT I don't recommend everyone change the entire unit. If you don't have major problems with for example oil leaks in the timing cover or noisy bearings, I recommend only changing the cap and rotor.

Far too many people have problems with the replacement opti or the install. Let me repeat that, far too many people have problems with the replacement unit or the installation. Your OBDII will report problems with internal optical encoders inside the distributor. So if your not getting DTC's for them, don't change it. Cap and rotors are available at good suppliers like Summit.