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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29456
Experience:  GM Grand Master Technician 2007. 14 years experience.
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96 Tahoe: loses power..under load..fuel pressure is good, coil is

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96 Tahoe 5.7 SFI loses power when warm at 2000 rpm or when under load. Has new cat, fuel pressure is good, coil is good, new plugs and wires. OBC indicates MAF responding. One bank shows 50% fuel trim when accelerating. Timing advance at idle -23, ranging to -30 when accelerating to 2000 rpm. Won't go much over 2000 rpm.

Welcome, and thanks for using Just Answer. I am Cam, and I will do my best to assist you. When you are finished please click on accept only if you are satisfied. I don't get paid unless you do.Please do not accept if you cannot leave positive feedback. I don't know if you are a tech or a just working on your own vehicle so we may have to fine tune the answer. I only know as much about your problem as you have told me in your post, so my answers will be based on what you tell me so please add all the details you can. About your vehicle, What pressure did you measure, what psi?

 

Customer: replied 6 years ago.
My mechanic checked the pressure while running it over the road thru its lose power phase, says it stayed steady at 60 psi.
I took it a mechanic after trying the obvious mysel (plugs, wires O2, cat), asking him to clean injectors - after he tried a bunch of other things he finally agreed it could be a restricted injector and flushed them today, but no difference in the way it runs.
I have a obc reader and laptop that I have used to log readings on 3 runs, can give you information from those if it will help.
Customer: replied 6 years ago.
My mechanic checked the pressure while running it over the road thru its lose power phase, says it stayed steady at 60 psi.
I took it a mechanic after trying the obvious mysel (plugs, wires O2, cat), asking him to clean injectors - after he tried a bunch of other things he finally agreed it could be a restricted injector and flushed them today, but no difference in the way it runs.
I have a obc reader and laptop that I have used to log readings on 3 runs, can give you information from those if it will help.

Have you replaced the cap and rotor? Cleaned the MAF or unplugged the MAP?

 

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