92 Lt1 Running rough...
Thread Starter
Racer
Joined: May 2004
Posts: 263
Likes: 0
From: Oconomowoc WI
92 Lt1 Running rough...
I have a 92 LT1 Auto Coupe (White w/beige, FX-3, Sport Seats) that I bought in May. It was part of an Estate settlement and had been in storage for over 1 year. I paid $6000 for this 90,000 mile 2 owner car. It has turned out to have been an excellent bargain and thus far (3000 miles this summer) I have really had no problems with it.
Improvements have included the obligatory spring LOF (Molil One), coolant flush, FI power flush,and a major tuneup- including plugs, wires, optispark (ouch), pcv valve, fuel filter. Modifications have involved, K&N cut box filter, 160 degree thermostat, tbi performance chip, moved MAT sensor, and ss Magnaflows.
The car has run absolutely fantastic all summer, smooth, fast, and cool.
Today, I take her out for what will probably be the last top off drive of the year and she is running rough. Idles slightly rough, but really noticeable under acceleration. When I put my foot into it, the response is really sluggish and it feels like there is a lot of detonation going on. Seems like 4-6 cylinders are firing. Under WOT it totally bogs down.
What is going on here- I put 100+ miles on her yesterday and she ran absolutely perfect.
Improvements have included the obligatory spring LOF (Molil One), coolant flush, FI power flush,and a major tuneup- including plugs, wires, optispark (ouch), pcv valve, fuel filter. Modifications have involved, K&N cut box filter, 160 degree thermostat, tbi performance chip, moved MAT sensor, and ss Magnaflows.
The car has run absolutely fantastic all summer, smooth, fast, and cool.
Today, I take her out for what will probably be the last top off drive of the year and she is running rough. Idles slightly rough, but really noticeable under acceleration. When I put my foot into it, the response is really sluggish and it feels like there is a lot of detonation going on. Seems like 4-6 cylinders are firing. Under WOT it totally bogs down.
What is going on here- I put 100+ miles on her yesterday and she ran absolutely perfect.
Team Owner
Joined: Mar 2001
Posts: 30,861
Likes: 293
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
Please tell me they flushed the cooling system before they changed the opti.
If so, check the codes, it could be the fuel filter or a clogged injector. Try disconnecting one cylinder at a time to pin point it.
Sometimes just sitting in a garage can do a lot of damage, most museum cars won't turn over!
If so, check the codes, it could be the fuel filter or a clogged injector. Try disconnecting one cylinder at a time to pin point it.
Sometimes just sitting in a garage can do a lot of damage, most museum cars won't turn over!
Thread Starter
Racer
Joined: May 2004
Posts: 263
Likes: 0
From: Oconomowoc WI
Oh, yeah- cooling system definitely flushed prior to OptiSpark replacement.
I understand about all the bad stuff that can happen when a car sits an extended period of time, but keep in mind that this thing has been running excellent all summer.
This condition just started today
I understand about all the bad stuff that can happen when a car sits an extended period of time, but keep in mind that this thing has been running excellent all summer.
This condition just started today
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Running rough....
Sounds like you should be throwing a code... check codes first. Sound like your opti. To check, pull your plug wires and check for a spark. That should be a good place to start.
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
you will want to check the following areas:
1) Coil wire - this can chaif and ground out, causing this problem.
2) Coil - yup... they do just up and quit.
3) Ignition module - the coil is attached to it. They also just quit.
4) Fuel pump - If it ain't pump'n, you ain't drive'n. Check the pressure with a fuel pressure gauge, should be at 43psi at idle.
Don't blame the opti just yet, check these other things. They will fail without throwing a code!!!
1) Coil wire - this can chaif and ground out, causing this problem.
2) Coil - yup... they do just up and quit.
3) Ignition module - the coil is attached to it. They also just quit.
4) Fuel pump - If it ain't pump'n, you ain't drive'n. Check the pressure with a fuel pressure gauge, should be at 43psi at idle.
Don't blame the opti just yet, check these other things. They will fail without throwing a code!!!
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From: Fort Knox, KY
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Don't forget to clean your throttle body, too. It's a good idea to inspect annually and clean accordingly. Really helps 'em idle smoother and perform better.
