I have a Camaro 3.4L V6 / 95 and it will not go over 4500 RPM when the engine is cold but when the engine is hot it will not go over 3000 RPM. The engine has normal power until it reaches 3000 RPM hot. It does not go over 3000 RPM when hot, it is like some magical barrier is there. The engine cuts off when it reaches 3000 rpm and drops down for some 100 or 200 rpm suddenly. It is behaving like when you reach too high rpm and the safety limiter is cuting off fuel... Please can somebody help me I am desperate… (Sorry for my bad English)… I am from EU - Slovenia and we do not have any serious service (repair shops) for Chevrolet cars here... Please can somebody help me and give me some hints or tell me where I could get this information….

 

Are you revving the engine up while under load or while in neutral? There is a safety feature in the PCM programming that limts the RPM while in neutral to around 3000. This is done to prevent damage to the engine, by revving it without a load.

 

Thank you for your reply z28pete. It is not the safety feature in the PCM, because the car is behaving that way in all gears or positions (neutral, park, DRIVE…) it is the same when the engine is under load or in neutral… When I accelerate the car accelerate normal until it reaches 3000 RPM. It will not go over 3000 no matter what you do… But when the engine is cold it will go to 4500 or 5000 RPM and than stop… The OBD tester did not show any errors. I have also tried and replaced new ignition coils, spark plugs and cables, MAP sensor. Throttle position sensor TP seems to be ok, but I am not sure also crankshaft position sensor and camshaft position sensor seem to be ok but I am not sure. Can they be the possible cause for the problem, or can it be the ignition control module under the coils…. Or maybe something else, can it be the computer…. I will be very thankful for any ideas…

pepe

 

hi pete am having the same problem to. i was drving on the expressway and i noticed that it wont go past 3000 rpm, now mine is an auto, with a computer mod on the pcm, cool air intake, and dual exhaust with a cleaned out cat...what do u think?

 

I think you might want to check your vacuum seals, on the 3.4, check the Upper Intake VacuumFitting for starters (at least that is what I would do),the RPM drop sounds to me like it is sucking way too much air-my 95 3.4will rev to 5000 easily in park/neutral/drive, though I rarely ever do so. Could be a bad sensor somewhere, is it throwing anything from a computer scan?

 

Well i had the same problem. When you say when your car is hot do you mean it is running hotter than normal or is it overheating. My car would drop way down into 100 200 rpm range because my car was overheating. I had a blown head gasket. Im not sure but this could be the problem if your car is overheating but other than that i would check the vaccum seal also as jtvyper said.

 

Pepe, I have to say, check your vacuum lines for cracks or disconnections. Also, if you don't find anything wrong with the lines, check your fuel pressure. Because, if your fuel pump is getting weak, your fuel pressure regulator is bad, or your fuel filter is clogged, your fuel pressure will drop causing your car to lose power at higher RPM's.

 

I have a 93 camaro V6 3.4L I changed the ignition control module cause it would sputter and pop through the intake and would not go over 4,000 rpms and now after changing the part if goes to 3,000 rpms and it back fires and trys to stall out I triple checked the firing order and it's all correct I'm getting frustrated with this I cant figure it out

 

Could be a timing chain problem.

 

Could also be a plugged Cat Or some type of fuel restriction.