Rpm problem

Asked by Feb 27, 2019 at 10:40 AM about the 1998 Mercury Sable

Question type: Maintenance & Repair

My RPMs shoot up to about 3000 before my car
hits 20 mph. After it finally shifts it seems to run
fine, although while idle RPMs bounce between
500 and 1000. At times it shifts normally but after
driving awhile RPMs will shoot to 3000 before I
even hit 30 mph. Any help or knowledge you could
share would be helpful. Thank you.

1 Answer


First: Check fluid. Low trans fluid causes all sorts of shifting problems... Second: A faulty PCM (powertrain control module) will affect shifting because it controls the gearbox shift mechanism. The PCM will have no input if the speed sensor fails and the transmission will not shift properly. If the condition persists after you check/fill the fluid, you should to get this to a transmission specialist.

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