1989 Buick LeSabre 3.8lt...free car but in good shape (sat for 2 yrs,but was started every cpl months)
She drives awesome, just had CV axles replaced....
Since we got car, she goes really good, cruise works etc.
However...when we are going down a hill, let off the gas to "coast", the idles "stumble". They'll be at 2500rpm (for eg) in OD, let off to coast & idles drop to 900 Rpm, back up to 2500 rpm, then back down, repeatedly...until we apply gas & she'* fine again..almost like she thinks she has a jake break
It seems to always do it, whether we touch the brake pedal or not...more so if we've touched brake...but does it either way
It does this with or without cruise on...have tried getting codes read, as SES light intermittently comes on, but doesnt change how she runs. Its not holding any codes to be read
She idles perfectly, no stumble, drives great & has awesome fuel mileage.
Have been told to try spraying carb cleaner into TBI..but kinda leery on doing that, dont want 2 cause another problem..any thoughts?