1986 stutters while driving, MAF or fuel problem
Thread Starter
2nd Gear
Joined: Apr 2020
Posts: 2
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1986 stutters while driving, MAF or fuel problem
My 1986 Corvette recently started having an issue with hesitating and jerking back a little after I let off the acceleration. It only happens after it gets up to 40+mph. Under 40 it runs normally, but once I accelerate past 40 and then let off the pedal, there is a noticeable jerk backwards, the car feels like it lost some power, as if I shifted it into neutral and it’s just coasting, and the MPG gauge shoots way up to 50-70. It stays like this until I start to accelerate again, the car jerks forward a bit like it’s getting its power back, feels like how a normal car would feel shifting from neutral to drive. And the MPG gauge goes back to working normally.
At the same time this problem came up, the car started idling high and rough at about 1100-1300rpm, a lot more exhaust smoke, and the service engine light came on. The codes came up as 22 (TPS) and 34 (MAF). TPS has been replaced and code 22 went away. Fuel pump and sending unit were both replaced too. The MAF burner and power relays were replaced, and after that I noticed the idle was smoother and at about 900-1000. I had 2 extra MAF sensors lying around, one was used and one was new. The used one gave the car a rougher idle but smother, less stuttery drive. The new one caused a really smooth idle at 600-700, but a bit more noticeable with the jerking problem. The code 34 has not yet gone away, although I only replaced the MAF a few hours ago, but I don’t think it will clear the way it is now even if I gave it a few days.
The issue did seem to get better with each part that was replaced, but it is still noticeable and bothers me greatly. The only thing left that I can think of is maybe bad wiring from the MAF sensor to the relays. Any advice on what the culprit could be or what to check next is greatly appreciated.
At the same time this problem came up, the car started idling high and rough at about 1100-1300rpm, a lot more exhaust smoke, and the service engine light came on. The codes came up as 22 (TPS) and 34 (MAF). TPS has been replaced and code 22 went away. Fuel pump and sending unit were both replaced too. The MAF burner and power relays were replaced, and after that I noticed the idle was smoother and at about 900-1000. I had 2 extra MAF sensors lying around, one was used and one was new. The used one gave the car a rougher idle but smother, less stuttery drive. The new one caused a really smooth idle at 600-700, but a bit more noticeable with the jerking problem. The code 34 has not yet gone away, although I only replaced the MAF a few hours ago, but I don’t think it will clear the way it is now even if I gave it a few days.
The issue did seem to get better with each part that was replaced, but it is still noticeable and bothers me greatly. The only thing left that I can think of is maybe bad wiring from the MAF sensor to the relays. Any advice on what the culprit could be or what to check next is greatly appreciated.
Thread Starter
2nd Gear
Joined: Apr 2020
Posts: 2
Likes: 0
https://www.oreillyauto.com/detail/b...corvette?pos=3
Im no so much worried about clearing the code, just fixing the problem. New MAF is installed currently and problem still persists.
Pro
Joined: Mar 2020
Posts: 500
Likes: 27
The MAFs are correct, the used one also came off an 86 and the new one is a "premium" part, it has a circuit board inside instead of the normal ring with filaments, like this one ->
https://www.oreillyauto.com/detail/b...corvette?pos=3
Im no so much worried about clearing the code, just fixing the problem. New MAF is installed currently and problem still persists.
https://www.oreillyauto.com/detail/b...corvette?pos=3
Im no so much worried about clearing the code, just fixing the problem. New MAF is installed currently and problem still persists.
You have access to a scanner to see MAF readings ?
Last edited by Theman5; Apr 3, 2020 at 09:30 AM.
