(5 jimmy idle's great new fuel pump, new fuel filter, the issue is that it runs great till it gets up to around 80 clicks and then the tack start going up and down one its own and engine races and the comes back to road speed don't know what else to do I fog the engine cleaned IAC sensor, the the srnsor in the air hose comming from the air filter. sprayed carb cleaner in to clean all the carbin out yet don't know what else to do to fix issue thanks for reading hope you can help.

 

What year?
What engine?
Does the check engine light work?
Is the check engine light on or flashing while driving?
Have you checked for trouble codes?
If so, what are they?

What do you mean by "till it gets up to around 80 clicks"?

 

Hi thereits a 95 jimmy and yes check engine has been on for some time even when it wasn't doing whats it is some one put an OBD2 computer in it and the reader I have one shows the abs and the egr codes nothing else gonna do a test and see what happens thanks will let you know Forgot to mention it"s a six and a 4.3 vortex sl And to your question till it get around 80 Well it wont act up below or above that

 

What are the actual trouble codes? They start with "P" followed by 4 digits. List each trouble code in the order they are retrieved.

"80 clicks", do you mean 80 miles per hour?

What is the engine RPM when it acts up?

 

80 mph or 80 kph

Sounds like fuel shutoff at max speed, mine does that at 99 mph

Maybe bad maf or vacuum leak

 

I agree, could be the rev limiter, but 80 mph seems low. If it's 80kph, that's only 49mph and WAAAAAAAAAY too low for a rev limiter.