So my 87 trans am 305 tpi wasnt running great to begin with (misfire, off and on code 34) but ever since i replaced failed intake manifold gasket it wont idle. Reset timing twice finding TDC, pointing rotor to plug #1. It starts, then dies. Does the same thing with MAF unpugged. Now i remember when the throttle body was off the minimum air screw was all the way out, not even keeping throttle blades open at all. I moved it a little forward and idled a little up to 300 or so rpms before dying. My mechanic thought the distributor was off a tooth and turned it clockwise/ CCW while i started engine but started backfiring. Now were gonna find TDC again with valve cover off. Any ideas where problem could be? Where should that minimum air screw be since i cant properly set it? And anything i could have broken electrical or otherwise that could have done this while changing intake manifold gasket. Thanks.

 

Get the base timing set correctly first, since that is critical. When that is set properly, review the connection and condition of vacuum hoses. When that is all intact and if it does not idle you will need to investigate the IAC system.