GrandpasBenz

I inherited my grandfather's cherry 1988 420 SEL, but it sat for 8 months undriven. When I went to pick it up, it started right up with a jump, but when I put it in gear and hit the accelerator, the throttle surges and cuts, surges and cuts, surges and cuts, all with many warning and check engine lights flashing. I have read many threads about idle issues related to the idle control valve, but not this particular surging issue. Also, it does not surge when in neutral, only when in reverse or drive, revs normally when in park or neutral. I am mechanically inclined, but have never dug into a project with so many variables. I would really love some direction from the experts before I start the process of trying to repair this crippling issue.

oldsinner111

It could be the gasoline is bad.