94 serging while driving ?

[blazer2007]

Have a 94 z 71 305 auto that likes to serge and buck while driving and I have to drop down a gear to bring the rpms up to clear it up.New fuel filter,cleaned tbi,and air sensor,new plugs and wires ,cleaned dist cap.It starts fine and idles fine.I,m new to this computer injected trucks so bear with me

[ChevyTech]

Originally Posted by blazer2007

... I have to drop down a gear to bring the rpms up to clear it up ...

That statement makes it sound like it may be running rich.

See this:
http://67-72chevytrucks.com/vboard/s...4&postcount=10

[blazer2007]

I read the thread,thanks, is the coolant sensor right by the thermostat?.Just because I need to know,why would a coolant sensor affect this,just because the engine might be hot or cold,why would it get involved with rich or lean

[blazer2007]

I did unplug the coolant sensor while running and got little or no variation in idle but engine was not up to operation temp if this means anything.

[ChevyTech]

Originally Posted by blazer2007

I read the thread,thanks, is the coolant sensor right by the thermostat?.

Yes

Originally Posted by blazer2007

Just because I need to know,why would a coolant sensor affect this,just because the engine might be hot or cold,why would it get involved with rich or lean

The computer uses the coolant sensor by the thermostat to determine how much fuel to inject.

Fuel injected engines do not have a choke like a carburetor does. The computer uses the coolant temp to determine how much extra fuel to add.

[ChevyTech]

Originally Posted by blazer2007

I did unplug the coolant sensor while running and got little or no variation in idle but engine was not up to operation temp if this means anything.

Unplugging the sensor should have set a trouble code in the memory of the computer.

If you did not notice much difference, there is a good chance the coolant sensor or the wiring to it are bad, or the engine temperature is about 40 degrees below zero.