I own a 1996 3800 series III v6 that I drove for a while and then let sit up for about three months. I moved from Texas to Louisiana and drove the car here. It ran ok for the drive but would not go over 60 and sometimes would not go over 45MPH. When I got here I tried revving the engine since I heard no pings, knocks, or other problems. I set the car up because of transmission problems and thought maybe this was the problem but I had rebuilt the transmission. It was just a simple leak but figured what the heck I will just rebuild it since it had 200k miles on it.

When I rev my engine it does well til it hits around 6k RPMS. It then drops to 4k and back up to 6k with the fuel pedal floored. It will continue to do this for as long as I have the pedal pressed. I was wondering what could cause this. I have checked the engine over and only thing I can figure is to get a fuel system treatment. Has anyone encountered this before and if so what was the fix?

I have not checked the fuel pressure as I do not have a gauge.

 

You not having a fuel pressure gage does not change the fact this could be a fuel pressure issue. That would be my step one, Second I would check exhause back pressure. But that is a differnet gage. Check your local parts stores for a loan a tool programs.

Is this with the car driving? are you slowing down 1/3 speed then speeding back up or are you just reving the motor up and bouncing off the rev limiter? Running a stock motor 6k with no load is asking the motor to please spin a rod bearing.

 

....or until the engine goes boom! You're pressing your luck abusing the engine this way, especially one with 200k miles.
I agree with Gorn on the fuel pressure check, your fuel system might not be supplying sufficient fuel which would be starving the engine (referring to your not going over 60 issue).

 

Thanks, will see about getting a fuel pressure test done. I do not rev the engine for long periods of time. Short bursts and only when the car is fully warmed up. I hate to rev without a load and could not figure out this problem. Thought maybe someone here has encountered it before so I posted here before I did any damage to my engine. I love my car and will be changing the engine out to a v8 hopefully within the next year. But I want to keep this engine in good working order also.

To address the not going over 60 issue. I was moving from Texas to Louisiana. A small journey of about 200 miles. I noticed it when I was driving. The trip started out ok. With a full fuel tank and a smile on my face I left. About 50 miles into the trip my car started slowing down. I fed it more fuel and it bogged down. I feathered the fuel and got it to a steady 45 miles per hour. After about 6 miles of this I was able to coax it up to 60 miles per hour. When I got into town and got going up a bridge the car jumped to life and shot up to 70 miles per hour. It then ran great until I got it here and then the next day took it for a test drive to have it do exactly the same thing. I got home and revved the engine to listen to the engine since it sounded perfect while idling. That is when I noticed the rpm problem and I shut it off immediately. Had a friend come over and he was baffled too. Asked around and no one really could finger it for me. SO I remembered this site and figured I would ask people who dealt exclusively with Camaro engines.

 

Alright Ardusv glad she didn't give out on you all together during your move. Let us know what that fuel pressure test reveals and we can go from there.

 

Have you ever changed the fuel filter? If enough dirt build up is in their, it definitely could cause your engine to show the type of symptoms you mention. Without going any further, I would surely change that fuel filter even if it isn't to old.

 

It is not how long you hold the motor at the RPMs it is the amount of RPMs. The acceleration and decceration is the problem. In many cases the decceration will cause the timing chain to jump a tooth or a rod bolt to strech. Never take a stock motor over 5K without a load on it. If every 3800 owner did what you did I would bet 5% of all the 3800's out there would not survive.

You are decribing a flow issue perfectly. My guess would be the fuel or exhaust can not flow but it is possible it is some type of timing issue and the spark is not advancing but that would not be a common issue.

 

I am by no means an expert, but could his issue also be due to an ICM going out? This sounds like what happend to me right before my ICM went totally out.

 

[QUOTE=Ardusv;When I rev my engine it does well til it hits around 6k RPMS. It then drops to 4k and back up to 6k with the fuel pedal floored. It will continue to do this for as long as I have the pedal pressed. I was wondering what could cause this. I have checked the engine over and only thing I can figure is to get a fuel system treatment. Has anyone encountered this before and if so what was the fix?
[/QUOTE]

Its called a rev limiter thats doing what its supposed to.