90 Lesabre deceleration miss......

Hey fellas! Im new to this and would greatly appreciate some insight!

My 1990 buick lesabre has a strange "lope" when you let off the gas at highway speeds and start coasting, or if the throttle lets up while the cruise is set when you start going down a hill. As it decelerates it drops approx. 300-400 RPM's and jumps right back up to where it last left off throughout the entire deceleration (about every 3 seconds), when you touch the throttle in the middle of a "lope/bog" it snaps out of it instantly. There isnt a thrown code or nothing. Also when i start it and its still kinda cold and i put it in gear, it sputters until i touch the gas and then its fine except for the deceleration issue.

Any ideas?? Thanks!!

Welcome to AF, try disconnecting the egr and see what happens.

thanks for the reply, disconecting the egr did not do anything.

you have a 3.8 or 3800 in it don't you? when i had a 87 pa and it ended being the tps after i replaced the module under coil pack. if your check engine lights on take it to auto zone and have them put it on there machine because it also could be coil pack. you might try some sea foam in your gas to see if it's a injector also whens the last time you changed plugs,wires, and gas filter? this is a shot in the dark because you could save money having it put on a machine instead of just replacing parts.