Chevrolet Repair: Chevy 2000 Silverado 1500 4.3 V6, fuel pressure regulator, spark plug wires

Question
The truck starts then idles high then low then high again over and over.  If I step on the gas it kills.  I have changed the distributor cap and rotor, spark plug wires, spark plugs, fuel filter, injectors, fuel pressure regulator, and fuel pump.
Hope you can help.  

Kevin


Answer
Hi Kevin,

Sounds like surging.  

Sounds like EGR issue.  If you don't have a service light on, you may have a problem at the valve.  You may also have a vacuum leak.  

Does this clear up when the truck warms up?  Can you get a vacuum guage and do you know how to use one?  If so, check the vacuum.  

May be a leaky injector.  For that you need to scan the O2.  

Hope this helps.

C J S