Vehicle is a 1990 Buick
LeSabre. Ran great for a while. Occasional minor drop in idle but nothing concerning. Recently engine would stutter when giving gas at 45 mph+. Maybe twice during a 20 mile trip. Been like that for months. Here in the last month it idles rough more often. Acts like its going to die when accelerating from stop. Does die when using reverse 75% of the time.
Added fuel treatment, no help. Plugs and wires replaced less than 7 months ago.
Unplugged Mass air flow sensor and ran it down the street. Still acting as before.
Here's the codes I got from auto store.
GM 21 thru 26
GM 32 thru 35
Im going to attempt cleaning the resistors on the Mass Air Sensor by dripping some rubbing alcohol on them.
Any help much appreciated!