dtfastbear

Hey guys,

I've got a stock (at least I *think* it is completely stock) LS1 out of either a 99-00 camaro. I've put it in to a miata chassis, and the car is a dedicated race car.

The engine has a very, very consistent stumble from about 5400 rpms to 5600 rpms. The engine pulls very hard right up to 5400, lays down just for a second or so, then pulls hard again right up through 6000.

I have access to a chassis dyno, and the dyno operator has the software to get into the PCM, but I'm wondering if folks have any theories on what I will find when I get it on the dyno?

Here's some in car video - you can hear the stumble just before I shift on the straights.

http://www.vimeo.com/11412173

Any ideas or suggestions appreciated!

Cheers,

Dean

PewterLS-1poweredSS

Its probably your valve springs. I had the same problem as you, changed the valve springs and it was gone.

PewterLS-1poweredSS

Mine would pull strong till 5000 stumble till 5400-5500 and then pull strong again until the rev limiter, but it happened everytime I rev'ed the motor that hi, never failed. You could also hear it, it was kinda loud, very weird sounding.