Troubleshooting help needed '95 LT1 A4
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,716
Likes: 0
From: Cartersville GA
Troubleshooting help needed '95 LT1 A4
Here's the deal. I drove (without any problems) to Pittsburgh Airport early Friday morning and parked it there for the weekend. I got in it this morning (Monday) and all was fine for about the first 40 minutes of highway driving. I stopped at a red light and noticed a really rough idle, it almost seemed like it wanted to die until I put in neutral. Got going again and was getting terrible gas mileage (around 9mpg), engine felt like it was missing, on acceleration the RPMs would go up, but she just did not want to go like she usually does. When I tried to hit passing gear I saw a large puff of black smoke from the exhaust. So I just limped on home with it like it was since I did not have the time or tools to deal with it on the road.
Now, I am thinking EGR valve or possibly bad wire and or plugs. What do you guys think?
Now, I am thinking EGR valve or possibly bad wire and or plugs. What do you guys think?
Race Director
Joined: Jan 2002
Posts: 12,261
Likes: 85
From: O'Fallon Missouri
Opti-Spark
I know this sounds like a broken record. But, it sounds to me like your opti is dying.
I've had EGR problems, and they are nothing like you are describing.
Good Luck.
-Mike
I've had EGR problems, and they are nothing like you are describing.
Good Luck.
-Mike
Instructor
Joined: Aug 2004
Posts: 144
Likes: 0
From: San Diego California
Troubleshooting help needed '95 LT1 A4
Sounds very similar to what happened to my '95 LT1 A4 recently. I got the "Service Soon" display when it started running poorly. It turned to be bad O2 sensors. Replaced the sensors and she runs like new again.
Burning Brakes
Joined: Dec 2003
Posts: 770
Likes: 0
From: Madison Mississippi
Long shot on this one. I think you have a bad plug. Look at the easy stuff first, like wire connections, plugs etc. It doesn't sound serious. Usually you can start worrying when you hear Knocking or major rattles. I hope this helps. 
The opti failure is the last on a long list of things to check.
The opti failure is the last on a long list of things to check.
Thread Starter
Melting Slicks
Joined: Jan 2003
Posts: 2,716
Likes: 0
From: Cartersville GA
Originally Posted by silver & red CE
Were any codes set?
Eric
Eric
Melting Slicks
Joined: Jan 2000
Posts: 3,418
Likes: 1
From: NW Chicago Suburbs
If codes were set, your SES light would be on. I just replaced my opti on my 96 LT1, it felt the the A4 trans was starting to slip, then it got worse (poor idle, hard starting), but no codes were set. I replaced the opti as preventive maintanince. When I pulled off the H2O pump I discovered the pump's seal had been leaking for some time, the opti was in it's first stages of death.
If I had an older LT1 Vette with your symtoms, I'd replace the opti, the wires, the plugs and the O2 sensors just as a matter of course. While I was at it, I'd slap a new H20 pump on. Otherwise, I'd just be worried about how well it was working. If you can DIY it, cost will be ~$600 from an Internet GM dealer like Dal.
Opti for 95-96 ~$200 (~$300 for 92-94 Opti)
H20 pump ~$150
2 O2 sensors (just the fronts) ~$80
Plugs ~$50
Wires ~$110 (for GM, you can save about $50 if you go aftermarket)
Eric
If I had an older LT1 Vette with your symtoms, I'd replace the opti, the wires, the plugs and the O2 sensors just as a matter of course. While I was at it, I'd slap a new H20 pump on. Otherwise, I'd just be worried about how well it was working. If you can DIY it, cost will be ~$600 from an Internet GM dealer like Dal.
Opti for 95-96 ~$200 (~$300 for 92-94 Opti)
H20 pump ~$150
2 O2 sensors (just the fronts) ~$80
Plugs ~$50
Wires ~$110 (for GM, you can save about $50 if you go aftermarket)
Eric
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