Falling on it's face

[chriskinzel]

Took the old gal for a ride tonight. Everything started ok running good. Decided to make a run up the canyon and she started not wanting to run past 3k. It did this regardless of what position the power key was in. I changed all injectors 750 miles ago, and both fuel pumps and filter last summer. It seems like a fuel issue, and I have not pulled out my fuel Preasure gauge yet. It seems fine if you keep it under 3k, or less than 1/4 throttle, but what fun is that! Any ideas from the great brotherhood?
Thanks
Chris

[SteelBlueZR1]

Sorry to hear your troubles. I would pull codes and see if you have any codes. You may have a secondary port low vacuum code, which I think is a code 61. My car behaved the same way when the secondary port solenoid went bad. Would stumble like hell above 3k and make no power. However, come to think of it... the car ran ok with power key off.
Also, definately check the MAP hose and replace it if it is not snug fit, and/or is not the oem design with a hard plastic tube. Jerry's Gaskets has the NOS part.

[tf95ZR1]

My car ran great up to 4K rpm then "fell on its face"
Vacuum reserve was used up so secondaries closed.
New vacuum pump: problem cured!

Just sayin'

This happened years ago at the Nellis AFB Mile Run,
Gathering West (lets do it again!)
Marc Haibeck happened to be there and diagnosed the
problem literally in 30 seconds. Also, Rick Jesperson
happened to have a spare pump with him!
Picture Marc sitting on my tire on the tarmac changing out my pump.
Priceless!

[Pete]

Yeap, sounds like secondaries are shutting down.

Check vacuum pump if it works and you have a 1990 -1992 get a long piece of vacuum hose and connect one end to vacuum pump the other to the MAP sensor under your ECM if all good look for vacuum leak.

Pete

[Paul Workman]

My pump worked fine till the day I decided to remove the secondaries as part of my FBI porting. If it turns out to be a vacuum pump, I'll give you mine to a good home.:cheers:

P.

[chriskinzel]

Thanks for all the advice. Sound vacuum related. I will check the pump for operation and leaks. I will also pull codes. Maybe it's time to remove secondary's. If I do yank them, do I need to get a chip from Marc H.? Whatever it is it sounds like some good under hood time with the tools! I will let you know what the outcome is.
Thanks
Chris :)

[chriskinzel]

Vacuum pump runs fine. After I tuen the key on it runs for about 2 seconds, the shuts off. Pulled codes and I have a 43. I seems to run fine until it gets hot, then it seens to have problems. Ideas>