83 s10 code 4-4 (running lean)

[iamsnakebit]

Hello,since I love this Blazer I would like to fix my problem.

1983 2.8 California model. Rebuilt about 30,000 miles back.

When I start to accelerate from a stop or increase my speed it bogs down like the accelerator pump isn't working.(manually depressing the acc pump will make fuel go into the carb.) When driving at a normal speed it also seems to randomly miss.
No backfiring or spitting back through the carb.
10,000 miles back I replaced the carb (rebuilt unit) Replaced the O2 sensor, fuel filter, pvc valve. cap and rotor, plugs and plug wires, air filter, vacuum lines.
I have rechecked the vacuum lines, checked for loose wiring and/or connectors being loose.
If I someone would provide me with a list of the most likely things to check it would really, really be appreciated.

thanks,iamsnakebit

[3100]

-connect carburetor fuel feed line to empty bottle, crank engine for 15sec.

-fuel pump should supply 1/2 pint or more in 15 seconds, if below 1/2 pint check for restrictions.

-disconnect fuel line at the carburetor, connect low pressure gauge, start engine. Pressure should be between 4 and 6.5 psi if not check for restrictions in fuel tank sender filter, lines or hoses

-disconnect inlet hose at the fuel pump and connect a vacuum gauge, then crank engine or run engine until maximum vacuum is reached. If your reading is less then 15in Hg replace fuel pump.

[iamsnakebit]

thanks 3100, I'll check this out this week.
thanks again, iamsnakebit

[ninecraven]

I have a 1996 LS with the 4.2 engine. Have same problem and I replaced the fuel pump. No change. Mine seems to be affected at speeds over 55 but not at all if you accelerate.

[3100]

Originally Posted by ninecraven

I have a 1996 LS with the 4.2 engine. Have same problem and I replaced the fuel pump. No change. Mine seems to be affected at speeds over 55 but not at all if you accelerate.

totally different engines and fuel pumps

[ninecraven]

I understand that there is a difference in the engine, I was hoping for some common ground on a similar problem. I guess it's time to start replacing sensors.