I'd appreciate any suggestions.
Don't know if it's related, or just coincidence, but here's how it happened.
After the two recent storms hit the gulf coast, I found myself low on gas
one morning, only regular unleaded available no matter where I searched,
being desparate and almost out of fuel, I had to settle for regular
unleaded, and with no octane booster for sale at this outlet, I opted for a
bottle of STP Fuel Additive and a few gallons of 87 Oct until I could find
some 93. Later that day I found only 89 Octane, so I pumped about 10 gallons
and added a bottle of Octane booster. Well, maybe coincidence, maybe not,
but a couple of days later my car began running badly, idling rough, like a
misfire, but not a steady miss, and when under load, it just sputters and
misses really badly. I have to accelerate really slowly in traffic to avoid
the really bad midfiring and sputtering, but even then it's still there.
Thinking maybe I pickup up some trash from the fuel tanks at the local
outlets since they were being filled, emptied, filled with the demand on
fuel, I changed the FUEL FILTER to no avail. Then changed the SPARK PLUGS
thinking the recent mix of additives, octane booster, low octane fuel may
have fouled the plugs. This didn't help either. Eventually I will get a
proper dealer diagnostic, but I haven't given up on fixing it myself yet.
I'm not convinced I don't have a VACUUM LEAK somewhere but have tey to
investigate it thoroughly yet. Maybe intake manifold gaskets, or any of the
numerous vacuum hoses. So, do you have any other thoughts on what to check?
I did a voltmeter check on the Throttle Position Sensor, and according to my
Bentley, it didn't check out, but I'm not altogether sure I tested it
correctly. When moving the throtttle plate slowly and expecting to see a
change in the resistance across the specified terminals, the value didn't
change at all, like I wasn't moving the throttle plate at all. Do any of you
have knowledge about TPS to know that it is definitely bad, based on the
results I just noted? What else on the M50 would cause this poor running?
I appreciate any help!!