1995 SIERRA HESITATION PROBLEM

[beebow]

Still having hesitation problems with my 95 sierra Z71 5.7 truck 102,000 miles. Changed:

Plugs

Cap

Rotor

fuel filter

O2 sensor

starter (old one was shorting out)

alternator

 

Sprayed the tbi with tbi cleaner, ran two bottles of techron through the tank.

It runs ok now but the idle stumbles intermitently and it hesitates while accelerating and when shifting to second. Could this be a IAC problem, or a throttle position problem. Is there a way to test the fuel pump without cutting into the solid line to put in a pressure sensor. I heard that there was test plug under the fuse block but can't find it.

[beebow]

Oh yeah and another thing. After the truck warms up I get a service engine light. the code is 44 by checking it the old fashioned way with the dash lights.

[torx]

It sounds like you have a gasket leaking. I would start with the throttle body. They tend to leak at the back of the t/b when the gasket breaks down. Test for leaks at the back before replacing all the gaskets for the t/b and riser. You could add a throttle body spacer at this time to supposedly get better gas mileage at this time if you already don't have one. You could also have a leak from the intake manifold.

[obstin8]

spacer on tb?

[ken1mod]

there is a schraeder valve on the fuel line neat the tbi. Air conditioner gauges work well to test the fuel pressure.

 

Ken

[obstin8]

Ken1mod, do you know about the spacer they are talking about? I think I cross threaded the fuel line on the drivers side this afternoon. Can this be taped out? Is there supposed to be a o-ring on both fittings? Dope tape? Need some help here and would really appreciate it.

[timt123]

Ken1mod, do you know about the spacer they are talking about? I think I cross threaded the fuel line on the drivers side this afternoon. Can this be taped out? Is there supposed to be a o-ring on both fittings? Dope tape? Need some help here and would really appreciate it.

 

One of the spacer brands is Air Raid; it lifts the tbi up about 3/4 of an inch and allows the fuel to swirl and atomize for better combustion. I have one that I paid about $75 for.

I'm not sure about tapping out the fuel line threads, though it seems plausable. You would probably have to helicoil it to get the correct size for the fitting. I know for a fact that there is supposed to be an 'o' ring on both lines and dope or tape should not be necessary.

Hope this helps!