Over the summer I put in a rebuilt bored out 350 (355) in my 88' TBI Blazer and when she's cold and you give it gas, it pauses for a second (as if it's not getting enough fuel) but then zooms right back a second later and runs pretty good at normal operating temp. Also, my gas mileage has worsened with the new engine (about 11 city). I've narrowed down the cause of this to 3 things: EGR valve, incorrect timing, and the fuel system(cam and TBI). EGR: I used the GM Vortec Intake (with EGR passage) as well as the vortec heads with the 64cc conmbustion chambers. And since my stock setup had EGR, I went ahead and installed the EGR valve and hooked it up to the EGR solenoid so I wouldn't have the "Check Engine" light on all the time. But as some of you may know, using EGR on Vortec heads with headers requires a fabricated EGR pipe from one of the headers to the valve. And since I am lazy and not very experinced with welding, I just left the EGR open so it would just suck in air from the compartment rather than hot exhaust gases. Timing: I have been messing with the timing on this thing since the summer and found that it runs decent at about 5-6 derees advanced (with the computer advance wire disconnected). I always run 89 octane gas. What are you guys with vortecs and tbi setting the timing at? Fuel System: I bought one of those tbi rebuild kits from Oreilly with new gaskets, seals, and filters and put this on the TB and cleaned it up really good. I'm thinking maybe the injectors themselves need to be replaced or rebuilt also. Also, JET sells an adjustable fuel pressure regulator for TBIs. Have any of you tried one of these? Would it work well with my setup? So, what would you recommend I do? Should I get a new chip? If so, what kind and where can I get it? Should I replace my injectors or have them redone? Also, I forgot to mention, I'm running a stock cam in this motor. Should I maybe look into a different cam? Thanks in advance for the help.