Lincoln/Mercury Repair: 2000 Sable Stalls. No OBD2 codes, mass air flow sensor, mass air flow

Question
2000 Sable DOHC. The car just had an oil change and air filter replacement. I also added a can of fuel cleaner. The car was running fine and then after a 130 mile trip it starts to stall. The rpm is about 400-450. What is strange though is when running 50 mph and you let of the gas, it idles back to about 500 rpm. I cleaned the mass air flow sensor and checked the EGR valve for vaccum leaks . All looks good. What could be causing this?

Answer
Hi Maurice,

Fuel cleaners tend to clog catalytic converters. But the idle back to 500 rpm at 50 miles an hour might indicate a transmission issue. You didn't mention if your check engine light was on or not, but I would imagine that it is. This means there is a code present in the car's computer memory. We will need to know what that is. Please take your car to a place where they can scan for this code. Dealers will charge huge for this, but a Cottman Transmission will do it for free.

Just a friendly tip... You remember the "snake oil" stories of the old west? All additives to anything in a car is snake oil.

Oh, sorry... I see in the title there are no codes. Well, you might try running a few tanks of Shell premium and see if it clears it up. A knock sensor will trip a code but won't turn on the CEL. I don't know if this is it, but all I can make out from what your telling me is the additive must be the cause.