1994 Grand Prix Coupe with the 3.1l SFI. When the engine is cold and i press the gas it bogs down. Ive looked this engine over top to bottom and cant find anything TB tps and iat check out ok. EGR is acting weird but seems to be doing the job. New airfilter on it, new plugs and wires. If I pump the gas pedal and press it down about half way the rpms go to about 1500 and 2 seconds later goes back up to normal rpms. This repeats until engine is warm. Please help