Engine revs acting strange
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Joined: Dec 2020
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From: Lansing, Michigan
Car: 1991 Camaro Z28
Engine: 305 TPI, LB9
Transmission: T5
Axle/Gears: 3.42
Engine revs acting strange
Hello all,
Trying to figure out an issue with my car and I'm not sure which tree to bark up.
I have a 1991 Z28. It has a 305 TPI and T5.
My issue is this: the revs act strange while driving the car. When I start the car, it revs up to 2000 and drops back down to around 750-1000 after a few seconds. It has very little power when I engage the clutch. As I start moving and shift gears, no matter the point where I shift, the engine always tries to rev somewhere between 1500-1800 rpm. So when I gun it, the revs drop down as they ought to. If I'm moving slowly, the revs will jump up in neutral instead of dropping. If I leave it in neutral, as I slow to a stop the revs will drop back to 750-1000.
A couple years ago, I replaced the head gaskets. While I was in there, I added Vortec heads and the Edelbrock TPI/Vortec adapter intake manifold. This manifold doesn't have provisions for EGR, so my friend and I did an EGR delete. We did not adjust anything with the computer. However, from what I understand, this should only affect the engine's timing, correct?
My speedometer works intermittently. I think my VSS is bad, but that part is nearly impossible to find for the T5. Could this mess with my revs?
I replaced my IAC the other night. On the first startup, the revs were right at 750 instead of the typical 2000 after doing the reset procedure. I then shut the car off--I didn't drive it at all. When I started it up again a few minutes later, it was back to its old tricks. Could it be that I did the reset procedure incorrectly?
I think one of those could be the culprit, but I'm not sure which. I'm also a newb when it comes to vehicle electronics--the few things I know, I learned from y'all on TGO. If anyone has had similar problems, I would appreciate the help a lot. I love the car but it's no fun to drive when it runs like this.
Thank you!
Trying to figure out an issue with my car and I'm not sure which tree to bark up.
I have a 1991 Z28. It has a 305 TPI and T5.
My issue is this: the revs act strange while driving the car. When I start the car, it revs up to 2000 and drops back down to around 750-1000 after a few seconds. It has very little power when I engage the clutch. As I start moving and shift gears, no matter the point where I shift, the engine always tries to rev somewhere between 1500-1800 rpm. So when I gun it, the revs drop down as they ought to. If I'm moving slowly, the revs will jump up in neutral instead of dropping. If I leave it in neutral, as I slow to a stop the revs will drop back to 750-1000.
A couple years ago, I replaced the head gaskets. While I was in there, I added Vortec heads and the Edelbrock TPI/Vortec adapter intake manifold. This manifold doesn't have provisions for EGR, so my friend and I did an EGR delete. We did not adjust anything with the computer. However, from what I understand, this should only affect the engine's timing, correct?
My speedometer works intermittently. I think my VSS is bad, but that part is nearly impossible to find for the T5. Could this mess with my revs?
I replaced my IAC the other night. On the first startup, the revs were right at 750 instead of the typical 2000 after doing the reset procedure. I then shut the car off--I didn't drive it at all. When I started it up again a few minutes later, it was back to its old tricks. Could it be that I did the reset procedure incorrectly?
I think one of those could be the culprit, but I'm not sure which. I'm also a newb when it comes to vehicle electronics--the few things I know, I learned from y'all on TGO. If anyone has had similar problems, I would appreciate the help a lot. I love the car but it's no fun to drive when it runs like this.
Thank you!
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