Low mileage/108,000 mi/1 owner (father) garage kept/excellent maintenance. Engine races after 150 miles (several episodes). I had local garage do a full tune up with plugs,wires, coil set and I think MAS. Car drove fine including several trips 100-200 miles, but now the problem has resurface. Starts with some whirring noises, bucking/lurching/over revving at low speed. Revs so high that I am can go 30-35 mi without stepping on gas. I am not automotivally inclined but trying to learn so I can have intelligent discussion with mechanic.
The mechanic is at fault by not reading the fault codes first
take it to an accredited service center and have the codes read , get the faulty sensors and have the mechanic do the job or have the service center do the fix
Problem with idle speed. The idle is controlled by the pcm (engine computer) through the operation of the Idle Air Control valve or motor. But several other sensors are also at work, like the throttle position sensor, the coolant temperature sensor, the MAP sensor or the Mass Air Flow sensor. The computer monitors all engine conditions to optimize performance and driveability-this includes keeping idle speed correct.
Would probably help you if you could see what all those sensors are telling the pcm-so you need a scanner capable of giving live stream data. And don't forget, your '94 is OBD-1, not OBD-II like all cars since 1996 on have. A garage should have such capable scanners, but they are kind of high end, not your typical cheap code scanner.
SOURCE: 1994 Ford Probe GT - Uncontrollable Revving
ok, this is simple to do but I would get the Chilton for your car so you can have pictures of what to do. You can get the chilton at the parts store, or the library. It sounds like a throtle body sensor or the throtle body itself, but could also be your air idle control sensor. go down and buy some mass air flow sensor cleaner and a BIG can of carb cleaner. First clean the mass air flow sensor neer the air filter. then remove the throtle body it is held in by 4 botls and you may need a new gasket, NO GASKET GLUE. Now take that big old can of carb cleaner and start cleaning in and out. also down into manifold. clean everything. Now put it back together, remember 4 bolts and no gasket glue. if the problem continues replace the throtle body sensor. and then the idle air intake. It will be cheaper to take it into the part store and have them put it on the computer. They can often tell you what sensor it is ahead of all this but don't let this stop you from cleaning out the throtle body, it will make your car run better and longer.
tepfy
SOURCE: 2003 Ford Crown Victoria misfires when
I HAVE HAD THE SAME PROBLEM ON SEVERAL CROWN VICS I HAVE WORKED ON ,& SOME OF THEM A SET OF PLUGS STOPPED IT,AND SOME OF THEM HAD TO HAVE 1 OR MORE COIL PACKS REPLACED, BUT THE PROBLEM THAT I FOUND THAT IF PLUGS & ALL COIL PACKS HAD BEEN REPLACED,AND IT WAS STILL IN THE IGNITION, IS THE WIRES GOING INTO THE PLUG ON THE COILPACK UNDER THE INTAKE TUBE, IF YOU REMOVE THE INTAKE TUBE,LOOK CLOSE AT THE WIRES FOR ANY BARE SPOTS,& LOOK AT THE BOTTOM OF THE INTAKR TUBE IF YOU CAN SEE WHERE IT HAS RUBBED IT,IT IS ALMOST A GIVEN THERE IS A BARE SPOT OR CRACKED INSOLATION ON THE WIRE, ENOUGH TO CAUSE A MISFIRE, (FYI) IT TOOK ME MANY TIMES OF INSPECTING BEFORE I LOOKED CLOSE ENOUGH TO SEE THE BARE SPOTS, BUT ALL YOU HAVE TO DO IS STRIP THE HARD PLASTIC AROUND THE WIRES BACK ENOUGH TILL YOU SEE GOOD CLEAN LOOKING WIRE,THEN SEPERATE THE WIRES AND IF YOU HAVE LIQUID ELECTICAL TAPE USE THAT AND THEN TAPE THEM WITH ROLL ELECTRICAL TAPE ,BUT IF YOU TAPE THEM UP GOOD SO WHEN THE WIRE IS BENT ENOUGH FOR THE INTAKE TUBE TO CLEAR ,& YOU CANNOT SEE THE WIRES GOING IN TO THE PLUG WITH A ROLL OF ELECTRICAL TAPE THAT WILL WORK TOO, I HOPE THIS TRICK WILL WORK AS GOOD FOR YOU AS HAS ME ON DOZENS OF CROWN VICS, ESPECIALLY P71 POLICE CARS.
SOURCE: How to change spark plugs and coil connector wires
Each coil mounts on top of the spark plug and is bolted down to the intake manifold with a 8mm bolt. You'll need to unplug the electrical connector to the coil, remove the 8mm bolt and pull the coil and boot up off the plug and out of the motor. You'll need a 5/8 inch spark plug socket, a ratchet and a 6 inch extension. Also a telescoping magnet with help getting the plug up out of the hole.
SOURCE: Engine misfire on 2003 FordTaurus
I have a 2001 Taurus with a misfire in #2, I've already replaced all the plugs, wires, and the coil. I did a professional fuel injector cleaning at a well-reputable shop, I then had that same shop spend a day and a half to diagnose it, and it turns out that it is a sticking valve in that cylinder causing the misfire, have them test the compression off and running to see if that's the issue.
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