It started happening a little while ago but not its doing it all the time. It seems like im gettinig fuel cut of the rev limiter is coming in at 6000rpm and only lets it crawl slowly to redline. I have a 05 z51 manual with 32000mile.

 

Are you sure it's the rev limiter? The rev limiter is really dramatic, the engine cuts off and on as the fuel is cut off, not just slows the revs.

See if a dealer tech will take a ride with you and have him watch a scanner, Tech 2, while this is happening. See if your getting a lot of knock retard. Sometimes knock retard will make it feel like it is revving slow. Might be actual knock or something rattling.

 

Well idk if its my rev limiter or not but even since I got the car the it would kick in initially at 6500 but if gas was still held it would go to 6700. It sound just like it but coming in hard at 6000rpms now.

Thanks for your help
Mike

 

I guess no one knows

 

check your plugs. you may be getting a high rpm miss.

i agree with michrider, the rev-limiter causes it to 'pop' (on/off). if you hold it there it will cause issues but the occasional hit-the-limiter isn't really a problem.

 

Is your Car stock??? b/c I just had the same problem, but I am modded

 

Your going to need someone watching a scanner while this is happening to really know what is going on. Doesn't really sound like the rev limiter, that only occurs at redline and you can't miss it - the engine shuts off and then toggles back on and off until you lower the revs.
A miss should set a code and turn on the CEL.

I'm leaning toward knock retard for some reason or low fuel pressure at high RPM or clogged injectors... those are a few things that won't turn on a check engine light but reduce power at high RPM.

If I was working on this car, I'd hook up a fuel pressure guage and tape it to the windshield and plug in a Tech 2 scanner. This way you can watch the fuel pressure and scanner data while the problem is happening. I've fixed many cars that techs couldn't figure out because they were only checking fuel pressure in the bay. A car requires a ton more fuel flow when actually out on the road under load at speed. That's where having the fuel pressure guage taped to the windshield will turn up odd fuel system problems.

This takes two people, you don't want to be messing with paging through scanner data while driving a car wide open. The scanner will show you if it's going lean, knocking, missing ... the fuel pressure guage will tell you if it's the fuel system causing this.

Could be something as simple as the injectors are getting clogged. Get some good cleaner with Techron. Chevron with Techron top engine cleaner or GM top engine cleaner is the same thing. Put a bottle of that in a tank of fuel will clean up the injectors.

 

I just have an intake and corsa sports but had it since 7000miles and no issues.

It started a little while ago but would do it only once and go away for a while but now it does its consistantly, and comes in just like the rev limiter, just a little less frequent pops and allows the rpms get to redline. The dirty injectors sounds like it might be true, because I often let the gauge get to the red line.

 

Not good to run it low on gas. The fuel pumps stay cool submerged in fuel, they can be damaged pretty easy running close to dry. A friend of mine ran his truck out of gas the other day. The fuel pump died the next day.

One way to tell if your fuel pump is weak is - it takes more fuel volume to run to redline in the higher gears. If it runs to redline easy in 1st gear, but struggles to hit the higher revs in 3rd and 4th, could be a weak fuel pump or other fuel system problem.

Should never pop, are you actually hearing pops like backfires? Even the rev limiter won't cause any pops it just toggles the fuel on and off.
If you are hearing any popping, something is wrong. A misfire, going lean, something. I'll bet it's a fuel system problem. Bad pump, clogged inlet screen... just guesses though, really need a scanner and fuel pressure guage to really know what is going on.

 

^^^^^^
i disagree. i pop on decel, (custom exhaust and headers). i also 'pop' when i 'bounce' off the limiiter. the fuel cutting off and on causes it to 'pop,pop,pop', telling you to let off just a tad.

 

I agree depending on what you have on the car (exhaust headers etc.)you will get that pop,pop,pop at redline. That is normal

 

I should say my cars never pop, its all in the tuning. But it sounded like he was saying his was popping when this revving problem was happening, and that definately isn't right. I can hold any of my LS vehicles against the rev limiter as long as I want and never hear a pop.


If he's struggling to get the last few hundred RPMs before the rev limiter should come on, that sounds like it's running out of fuel. Just a guess. And that will make it lean pop.

All the rev limmiter is - is cutting off the fuel, toggling the fuel injectors on and off. So a fuel system problem at high RPM could feel real similar to the rev limiter. Ignition system problems generally show up under high load, fuel system volume problems show up at high RPM high speed like right in the traps at the 1/4 mile. A drag car popping through the traps is usually running out of fuel pressure at the top end.