I have a 98 chevy 1500 pickup with 5.7 auto. It starts and runs fine till you open the throttle about half way or more. When you get it to that point it stalls or stumbles and it doesn't matter if it sitting or driving. I picks back up and runs fine when you let off the pedal enough. I have checked everthing I could think of. Also there is no codes showing or pending. Any help will be appreciated. Thanks
How long since a tune-up? Use a gage and check fuel pressure. If you have the spider fuel system, it is noted for problems.
February, 10, 2011 AT 9:43 PM
I should have stated what I have done. The fuel pressure is fine, I checked that, I installed new plugs cleaned cap and rotor, cleaned and even replaced the mass air meter, and had the ignition module tested and it showed bad so I replaced that. Still same problem. The tp sensor reads right as far as percentage of being open, as well as the ect, and the mass air.
February, 10, 2011 AT 9:58 PM
Sometimes the fuel poppets need cleaning. The procedure I saw was a shop procedure, don't know if injector cleaner in the gas tank will help or not?
Compare tps sensor signal to map sensor signal at idle. If several volt difference, something wrong.