90 GM surging

my 90 GM is surging at low speeds. tune up has been done about 6 months ago using NEW FORD parts, IAC has been cleaned, new air filter, TB cleaned, Seafoam treatment, new fuel filter and a new PCV valve. the motor has about 60k on it and runs STRONG! just it surges at about 30 mph or so. all the fluids have been changed except the trans which was done a month before my freind bought it 7 months ago.

this is a non MAF car, exhaust is new as of about a year ago from manifolds BACK including cats. i REALLY like this car and dont want to have it screw up on me to the point i cant drive it anymore without major work. any ideas are appreciated!

thanx guys!!!!

Check for any vacum leak. they usually affect performance only onlow speds.

ElMarquis

will do. havent heard any but that doesn't say much.