Recently rebuilt the 454 in my 1990 TBI Burb. I am having a terrible time with getting it to idle smooth. The engine has a little over 500 miles on it. I have spent countless hours going over the engine looking for vacuum leaks and believe every thing is OK on that front. I have replaced the engine temp sensor, the connections to the coil, the coil, cap, rotor, plug wires, map, checked the tps, reset the base idle, checked voltage values at the tps connection, map connection etc. The iac was replaced about 4000 mles ago. The throttle body was re-bushed about 4000 miles ago. The egr seems fine. I took it off and cleaned it. Checked it with a vacuum pump both on and off the truck. The engine is all stock except for the Edelbrock manifold. The truck idles like crap in park, but idles smooth in drive. It seems worse cold then after it warms up.
I took it to get smogged (Ca) and it failed (high NO). The tech said it would pass easily with a new cat. The old one was just 2 years old. About the only parts that aren't new is the O2 sensor (replaced 2 years ago), the iac and the egr vacuum solenoid.
I am about ready to pull my hair out with this one.
Thanks Brad
I took it to get smogged (Ca) and it failed (high NO). The tech said it would pass easily with a new cat. The old one was just 2 years old. About the only parts that aren't new is the O2 sensor (replaced 2 years ago), the iac and the egr vacuum solenoid.
I am about ready to pull my hair out with this one.
Thanks Brad