Surging
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Surging
I have a 1989 vette, rebuilt L98. The problem is that the car surges at idle, and it also surges at city speeds. Once at Hwy speeds(65-75 MPH), it drives ok! I checked for vaccuum leaks, and none was found. Checked the fuel pressure, ok (38 psi). Replaced PCV. Replaced air filter. Fuel pump and filter, less that a year old. Replaced all relays. Checked spark plug wires, ok. Pulled codes, with the following results: 12, 13, and 33. Changed oxgen sensor, code went away for a day. I unplugged the MAF Sensor, and the RPM went up slightly, but were much smoother. Repluged MAF Sensor, disconnected battery to clear codes. The car ran fine, for awhile. Now, I am back to square 1, but no code 33. I am thinking about replacing the MAF sensor. I replaced this MAF sensor approx. 6 years ago, with a rebuilt one, prior to storing the car for 3 year. Can anyone help me out?
Last edited by Sirwilliam1229; Aug 13, 2006 at 07:42 PM.
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Originally Posted by Sirwilliam1229
I have a 1989 vette, rebuilt L98. The problem is that the car surges at idle, and it also surges at city speeds. Once at Hwy speeds(65-75 MPH), it drives ok! I checked for vaccuum leaks, and none was found. Checked the fuel pressure, ok (38 psi). Replaced PCV. Replaced air filter. Fuel pump and filter, less that a year old. Replaced all relays. Checked spark plug wires, ok. Pulled codes, with the following results: 12, 13, and 33. Changed oxgen sensor, code went away for a day. I unplugged the MAF Sensor, and the RPM went up slightly, but were much smoother. Repluged MAF Sensor, disconnected battery to clear codes. The car ran fine, for awhile. Now, I am back to square 1, but no code 33. I am thinking about replacing the MAF sensor. I replaced this MAF sensor approx. 6 years ago, with a rebuilt one, prior to storing the car for 3 year. Can anyone help me out?
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I've followed the list of things I should do, as printed in the service manual. The manual tell you to unplug the MAF, and if the engine stabilizes, replace the sensor. I am searching for additional advice, due to the fact that we are not talking about a $3.00 part. I don't want to throw cash at the problem.
Safety Car
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From: Poop land
Plug up the 2 vacuum ports where the EVAP vacuum lines run and eliminate that mess completely. It beautifully solved my 16 month surgy idle problem. No more stupid vacuum lines and canister to ever worry about. If you still wanna keep the EGR system, you can just run a little vacuum line to it and it should be fine and functional.
Le Mans Master
Joined: Oct 2003
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From: seattle WA
Well, it does sound like it could be a vac. leak, but disconnecting the MAF and having it improve really points toward it. Did you also replace the FP relay? it plays a part with MAF functions. And before throwing that kinda money at it, besides the above have you checked the TPS voltage?
Instructor
Joined: Jul 2006
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From: Cary North Carolina
Originally Posted by kopbet89c4
Plug up the 2 vacuum ports where the EVAP vacuum lines run and eliminate that mess completely. It beautifully solved my 16 month surgy idle problem. No more stupid vacuum lines and canister to ever worry about. If you still wanna keep the EGR system, you can just run a little vacuum line to it and it should be fine and functional.
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From: Poop land
Originally Posted by shilly
Has anyone else done this? Are there any performance/driving problems with doing this?