94 Blazer 5.7 Missing and Hesitates when Excellerating

[blazer1994]

Hi All,

I have been having a problem with my 94 Blazer 5.7, Automatic, 205K miles.

No problem starting, but when started first thing in the morn, it idles fine, but once on the road, and I excellerate it hesitates and almost cuts out, no power. Once it warms up, it seems to get better. But has rough idle, and still hesitates on excelleration.

Things Ive done or had done. Replaced plugs (couple of plugs were vry corroded), replaced Air Cleaner, used bottle of injector cleaner.

Took it to the dealer, they put it on the computer and no codes showed up, the first time.

The second time at the dealer, left it over night so they could see the problem when cold. They replaced Dist Cap/rotor, oxygen sensor, and fuel filter. But I am still having the same problem. I am wanted to get a little smarter before going back to dealer again.

Any ideas????????


Help would be most appreciated!!!

[chevystepside]

well a 5.7 liter is a 350 and they really were not made to have many miles on it so i would get it rebuilt

[tom3]

First guess would be fuel pump, pretty classic symptoms. Need to actually check the pressure to be sure what you have. Seems like dealers these days want to plug it in and reset something or they won't mess with it. Is this still a throttle body injection system? If so, try unhooking the fuel return line, this is the smaller fuel line on the throttle body, and turn key on while watching for fuel flow in this line. If no flow I'd again guess failing fuel pump. Outside chance of a clogged catalytic converter, do you hear any hissing noises while accelerating?