2000 Taurus - RPM drops/spikes?

NEW FILTER NEEDED ON CARBORATOR I THINK.

Gasoline is gasoline in that most come from the same plants, except the major brands put cleaners in them to stop injector fouling.

My guess of the month is the check engine light is on and the engine is missing on a cylinder or one of the PCV hoses has a crack in it .. with the miss being most likely

A taurus missing on a cylinder will do the same things you describe and will produce a bucking like sensation while driving when the misfire occurs espcially going up a hill or something that will put a load on the motor at low to medium RPMs

also as someone said, clean the throttle body as city driving tends to clog them around 50-100k and causes rough idle/killing at times when slowing down or at idle... never going down the highway

Please even if you just go to the zone, have it scan tested by them for codes to get some ideas

Ford Spikes

Sounds like the Camshaft postion sensor may be going out, Could be a lot of things, Is the Check Engine light on? I would start by having someone check codes, I have seen the sensor im talking about do this before.

Had a taurus wagon very last month did an analogous element. each and every of the similar old fixes, thermostat, flush did not help. The water pump impeller became eaten remote from rust. Why it did not overheat, I dont recognize, yet I strongly suspect it is your situation

get a fuel injector cleaner, maybe an octane booster.. check the plugs, and the plug wires.

some cars just dont run well on regular gas, my f-150 will knock and run like crap if i put regular in it, always has to be midgrade or supreme.

could be an idle sensor or something

dont know if its tranny but i have an 04 taurus and it tries to die and will idle down and then back up... had it in the shop 5 times they say they fixed it but i cant tell .goin to the shop monday the 21st and raise h*ll good luck w/ yours.................... they replaced a idle air controll, mass air flow censor said had a pinched wire and then they put a new computer in it still messed up

DOES THE CAR HAVE A SERVICE SOON LIGHT ON? IF IT DOES GO TO AUTOZONE AND HAVE THEM RUN CODES IT IS PROBABLY THE IDLE AIR CONTROL VALVE GOING BAD REPLACE THAT AND DO A THROTTLE BOBY CLEAN AND IT SHOULD FIX THE CONCERN ALSO CHECK FOR LOOSE OR BROKEN VACUME HOSES

sounds like a loose connection in the ignition circut, causing the tach to act up and the car to stall, not gas or trans, possibly lack of maintenance but doubt it, they probably disturbed something when they did the trans work