4000+ RPM tach fluctuates, why?
#1
4000+ RPM tach fluctuates, why?
Hi, I have a 1997 camaro rs v6 3.8L car and for some reason when I rev the accelerator pedal to bring it up above 4000 RPM in idle, the tachometer will flicker just past 4200 for a millisecond then go back to 4000 then back to 4200, and so on. In Idle, even when I floor it, it never goes past 4000 RPM.
also... two of the bolts that connect the exhaust manifolds to the exhaust pipe are broken off (one broken on each manifold), so each exhaust manifold is only holding onto the exhaust pipe via 1 bolt. Could that have anything to do with it?
also... two of the bolts that connect the exhaust manifolds to the exhaust pipe are broken off (one broken on each manifold), so each exhaust manifold is only holding onto the exhaust pipe via 1 bolt. Could that have anything to do with it?
#2
1) That is the rev limiter trying to keep silly peple from damaging the engine when the engine is in neutral. Revving the ingine with no load can cause serious damage and the rev limiter is set to come in at low RPM when the engine is not uder load.
2) NO!
2) NO!
#3
Ok, good to know! I only revved it in idle for about 5 -10 seconds, so that didn't hurt anything, right?
also, my car seems to accelerate a lil slowly when it is on the road. Could that be because of an exhaust manifold leak?
also, my car seems to accelerate a lil slowly when it is on the road. Could that be because of an exhaust manifold leak?
#6
well, whenever I put my foot on the accelerator, it doesn't seem to want to move much on a cold start until the pedal goes about 1/3 the way then it goes from nothing to gunning it - split. Transmission problem maybe? <--but it never did that before I fixed one of the cylinder heads (passenger side) (I never did anything with the transmission).
The strange thing is, It doesn't seem to me like it is a TPS problem, because I can hear it trying, it just doesn't seem to want to go anywhere till 1/3 to 1/2 throttle.
I am not getting any codes either. Had it brought into an auto shop to flash the PCM recently, but it did this before it was flashed also.
The codes I did get, before taking it to the auto shop were map sensor signal too high (po108) but the shop said that disappeared after the PCM flash and 20 miles test. Also, one time (I have not been able to reproduce it) I had gotten some sort of code relating to my TPS.
Also, when I am driving the car, it seems to seem like it is trying harder than it needs to. In short, it feels like it takes more umph to get the same speeds.
The strange thing is, It doesn't seem to me like it is a TPS problem, because I can hear it trying, it just doesn't seem to want to go anywhere till 1/3 to 1/2 throttle.
I am not getting any codes either. Had it brought into an auto shop to flash the PCM recently, but it did this before it was flashed also.
The codes I did get, before taking it to the auto shop were map sensor signal too high (po108) but the shop said that disappeared after the PCM flash and 20 miles test. Also, one time (I have not been able to reproduce it) I had gotten some sort of code relating to my TPS.
Also, when I am driving the car, it seems to seem like it is trying harder than it needs to. In short, it feels like it takes more umph to get the same speeds.
#8
I didn't time any valves. I had taken the cracked head (yes, just one, couldn't afford to get both worked on, the other one is fine for now though) to a machine shop. They had replaced the valve seals, and repaired the crack.
and as far as setting the rockers...I don't think I did that wrong, but that's easy enough to double check the book.
and as far as setting the rockers...I don't think I did that wrong, but that's easy enough to double check the book.