I have a 94 3.4 V6 with 130,000 mi. on it. Recently I installed Flowmaster Exhaust on it. Since then I've noticed that the slight back-fire that was there before the Flowmaster is now amplified by it. I've been holding out on doing anything because the back-fire wasn't that bad to begin with. Now I want to get rid of the back-fire, and have been told by many people that it may be the timing or fuel mixture. I already know that my EGR valve is sticking, but I want to know how to adjust the timing of a car that is distributerless and has a timing chain instead of a belt. Can I do it myself?