1994 Chevy Z71with 350 TBI, surges Just off of idle.

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bimmster1 - 31 Jul 2006 17:01 GMT

Idle is only sligtly rough, but Engine surges when throttle is opened
slightly. This happens when driving slow and steady with engine warm. I
can duplicate with air cleaner off and hand open throttle. Spray from
both injectors is even fan and can be seen to increase and decrease. No
Tach is present to log RPM. I have change throttle position sensor
trying to solve this. Also Cap/Rotor, wires and plugs as part of
regular maintenance. All Looked OK but changed any way. There is no
fuel pressure gauge or place to install one that I can see to determine
fuel problem.

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grockswo - 31 Jul 2006 19:58 GMT

Might want to try changing inline fuel filter on the frame rail. Also,
check the IAC to make sure it is working properly. Make sure the TPS
is set correctly, there is an adjustment for mine, it should read 0.6
volts when you back probe the sensor wire on it, there should be 3
wires, one is a ground, one is a 5 volt sensor feed. The 0.6 volts is
when the throttle plate is fully closed. While back probing, slowly
open the throttle by hand, do this with the ignition on, but the engine
off. It should increase slowly and steadily up to about 4.5 volts, if
it jumps around or doesn't increase smoothly, you might have gotten a
bad sensor.

Gus

> Idle is only sligtly rough, but Engine surges when throttle is opened
> slightly. This happens when driving slow and steady with engine warm. I
[quoted text clipped - 5 lines]
> fuel pressure gauge or place to install one that I can see to determine
> fuel problem.

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