rohn1

I have a 1990 454SS that runs perfectly below 4000 rpm, but once I go above 4000 rpm it starts missing. I've replaced the plugs, wires, coil, cap, rotor, and nothing really changed. Could it be the ignition module? any suggestions would be appreciated. Thank you

MT-2500

Welcome to AF
I would check the rev limiter on it.
Are you testing or does it do it sitting still or on the road?

__________________
Remember proper testing gives us the answer to many problems.
MT

rohn1

I haven't started the truck up this year yet (weather just started getting nice) but it's had this problem since I purchased the truck 5 years ago. It has 57000 original miles on it, all pretty much stock. I'm not tuning yet but would like to soon. What was the rev limiter originally set at, and how do I can it.

Thanks for your help
Ron

MT-2500

I am not even sure it has one.
If so some are set in the 4K RPM range.
If it has one I would not touch it.
Is there any place that you need to go over 4K RPM?
MT

__________________
Remember proper testing gives us the answer to many problems.
MT

rohn1

I really don't have to go over 4k, just was wondering why it did that.
Thanks for the help