Recent content by Dave111

Originally Posted By: Merkava_4 Usually with driveability problems without a check engine light, you've got to start testing sensors with a lab scope. When they hiccup, the wave will change or they'll be a quick spike in the wave. My scan tool will graph the sensors as a wave. Is that what you...

Originally Posted By: Iowegian I'm convinced the issue is coming from the combustion chamber area. How negative is short term and long term fuel trim running? They both tend to be around zero, but occasionally neg 1-2% for both. Rarely, positive 1-2% briefly, after higher rpms. Also, I just...

Wow lots of good advice here. I'll answer in order. I did some more investigating today. As for O2 sensors, I can graph them on my scan tool. They both show what is reported to be normal waves pre and post cat. Can one of them be bad anyway? Did a fuel pressure check. The gauge reads 50 psi...

Have a 2002 Monte Carlo SS 3.8L with 83K miles. For the past few months, have noticed a slight wavering in the dash tach when sitting at a light. When listening under the hood, you can hear the engine subtly stumble once every few seconds. Otherwise engine seems fine, and has good power. No...