This past January (I live in Minnesota), I started to have an issue with my 2002 Ford Focus 4D SE (120,000 miles, automatic transmission). Sometimes (not always) when I first start the car, either at home or after it’s been in a parking lot, it starts just fine, but the car crawls when I step on the gas. Even with the pedal on the floor, it still crawls. At the same time, the speedometer doesn’t engage, and the odometer is blank. The engine light is on, too. Then, after the car has traveled a block or so, the speedometer and odometer snap on, the locks snap shut, and the car runs normally. I can get the car to go forward at somewhat normal speed if I put the car in second gear. Again, after a block or two, everything snaps back and I put it in drive. I have taken the car to a mechanic more than once. The mechanic said the engine light indicated that the speedometer sensor needed changing, but I was not convinced that would fix the problem, and didn’t get the sensor changed. I have asked the mechanic to check the electrical wires, but I don’t think they did. I have also had a new battery installed. In May (when it got warm again), the engine light went off and the problem ceased and the car ran normally.But in the past couple of days, the car has started crawling again. Does anyone know what’s going on? Would changing the speedometer sensor solve the problem, or is it something else? The mechanic can’t seem to find anything else wrong with the car.
Yes, it is possible that you need to replace a speed sensor.
However, it is also possible that this problem is related to a bad electrical ground.
I say that because I had the exact same problem with a Volvo that I owned.
In the winter, when temps were below 30 degrees, none of the instruments (except the speedometer) worked, the engine lacked power, and all of the lights operated on what appeared to be 1/2 of their normal brightness.
Once the engine reached operating temperature–in this case, about 10-15 minutes–it was like throwing a switch. Suddenly, full power would be restored to the engine, the dashboard, and the lights. It turned out to be a bad electrical ground, but it was a devil of a problem to track down, due to the nature of the Volvo electrical system.
My suggestion is to take the car to an automotive electrical specialist. There are not that many of these shops, but they do exist, and they can usually accomplish the task faster than most other mechanics.
Thanks very much, VDCdriver!
I’m guessing the reason the check engine light went out after the battery was replaced was because the OBD system reset itself. Since the problem is happening again, I would suggest having a scan tool read any “pending” codes that may exist. If a pending code comes back indicating the speedometer sensor, I would replace that first. This could be the cause of all your problems and since one mechanic already mentioned this AND the symptoms point to it, I would replace it. The speedometer sensor is not an uncommon problem on certain Fords.
Thanks for the advice, ebko87.
Hard to say without replacing it, but it’s possible the speedo sensor could be the ultimate cause of this symtom. The ECM uses the speed as part of the inputs to its calculations, so it may be confused when it seems otherwise to the ECM the car is running, the transmission is engaged, the driver is stepping on the gas like would be the case if driving down the road, etc, but the speed being measured is zero. It may be that the ECM has a backup plan, when the speed snensor input is bogus, after a certain amount of time of zero speed being sensed, it just gives up and ignores the speed parameter in its calculation, so the car goes back to acting like normal.
Thanks for the advice, GeorgeSanJose.