Last night, as I pulled out of the parking lot, my RPMs dropped below 1000 (no response to the gas pedal), then the engine cut out. I tried a couple of times to restart, but it just cranked without catching. I threw it into neutral so I could coast backwards off to the side of the road, and then it started up (transmisison in Park) when I tried again.
This morning, I got into the car and it would just crank but not turn over. Trying to put down the pedal before/during starting didn't seem to do anything. I had to run for the bus, so I didn't have any time to troubleshoot (can't even remember if the SES light was on), but at this point I can't even get it started to get it to a mechanic. Any suggestions would be welcome.
Relevant and irrelevant facts: '98 SL2 automatic, 66K miles
Two days ago I took it into a shop that I trust because I mistakenly thought I needed new brake pads (turns out I was hearing squeaks from metal in the pads, I guess)
Battery reads a little over 12 V
I have noticed a gradual decrease in MPG over recent months, from about 28 to about 20, and I have noticed a new rumble/sputter on maybe the left side of the car.
Alternator and battery were replaced about 2 years ago.
I replaced the oxygen sensor and plugs and wires last year.
I run a tank with B-12 chemtool about once or twice a year.