NSTG8R

I noticed it a few months back after I installed my x-pipe (x-pipe and cat assembly was used) .. i've got an rpm block that it takes longer to get through.

was checking the plugs today, which were in ok shape and also noticed a tick .. not sure if it's a normal tick or a lifter tick but was wondering if it could attribute to my rpm bog.

also have some clutch problems .. problems shifting, chattering and so forth but I dont believe it's the cause of this.

another thought that came to mind was is it possible for cats to be clogged and do that to an rpm section?

thanks.

vettenuts

Clogged cats will result in a constant decrease in power with RPM. Wondering if you have knock retard that is causing your bog. Also, there are some distinct harmonics with the LSx engines, what RPM?

NSTG8R

~ 3.5-4 to 5ih it'll get to that point fine but once it gets there woof it just is so sluggish.

sometimes it does it other times it doesn't so retarding the timing is a possibility .. plugs maybe?

RED99

Put it on a Dyno and check your A/F. Sounds like you are running out of fuel pressure on the high end. Maybe you need a new filter. But it could be your Cats too, since it did it after you replaced them. Can you put your old ones back on for a test? But I would confirm your A/F ratio first.

NSTG8R

my old ones are attached to an H-pipe .. so i'll leave it until I do my header install w/ high flow cats. If it's still doing it then I'm going to guess and say it wasnt the cats and just needs a tune.

vettenuts

My 02 stock had knock retard at 4,200 really bad. You could see it on the dyno. It took the tuner a while to get that one straightened out, but it made my header installation look as though I didn't get much down low when in fact if you look at how the car should have run without the knock retard it would have shown better gain. He told me some years have very aggressive spark advance.

NSTG8R

well i'll see how it is after the headers .. if it's there or worse .. then i'll dyno tune it.