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

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.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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
bimmster1 wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.