Hey,
I own a 98 z71 and when im going up a long hill it will stall out . And when travelling on the freeway with cruise on it will stall out when it try to pick up speed by kicking down a gear. I have replaced the fuel pump twice now and the fillter . I hook up a pressure gage and taped it to the windshild to watch the fuel pressure when im driving , It is perfect not one glitch and at idle she is so smooth it almost feels like it is not running.
Also when driving aound town(normal) not a problem ever .

So it seams like only under heavy load (up hill,freeway exeleration)

Any ideas?

 

I would try pulling out the sensor before the cat converter, and see if it runs any better.
If it has a mass air flow, make sure thats clean as well.. It can cause power loss and make it act real sluggish at times.

 

I will try clening the mas and test is as well to see what reading it get and compare it to specs . And as for the sensor ?? Your refering to the O2 ?

Thanks

 

Update
Everything checks out no codes but still stalls out under heavy loads.
There other day it tottally went dead and had to tow it home, figured it was the fuel pump again since it did not turn on at all . So took off the box (tanks was full) and checked for power first at the pump and nothing. checked all fuzes they where ok and finaly traced to the the fuse block under the hook(bad connection) So fixed that and got it running BUT the original problem still remains?!?!?!?!?!?!?
Also noticed a gurggleing sound coming from under the throttle body witch I never heard before on any of my chevs.

If anyone has any Idesa please pass them on!

I think im going to order new spiders and everything and just replace them and try eliminaating things .