I have a 1993 Ford Ranger 3.0L V6, Automatic Transmission. The truck has 217,000 miles on it. Recently I have noticed that at high speeds, normally around 50-60 MPH, the car jerks violently as if it is misfiring. Also, while this is happening, the tachometer jumps in a range of around 500 RPMs. This only happens as described at high speeds or while under heavy load (up a giant hill, trying to pass someone). When driving around the city, it runs pretty well, except for a little rough at idle. I have also noticed that even at idle the tachometer bounces a bit, but not nearly as pronounced as it does at high speeds. I have already change the fuel filter and had only small improvements, if any. I get a check engine light from time to time, but it disappears after a few minutes, only to return again a while later. What could be the problem?

 

if the check engine light only comes on for a few seconds is it blinking? blinking check engine light indicates a misfire. start with the basics check your spark plugs and wires. distributoress ignition? check the coil packs, go to auto zone and borrow the scan tool to see which cylinder is misfiring. check the injectors. my 2.5l ranger did that as well and i had a bad exhaust coil pack and a bad cylinder 1 injector.

 

I had the same problem with my Ranger. Still haven't figured it out.

 

A 1993 is not an OBDII system, so it would not blink the check engine light to indicate a misfire. You might get a lean code out of it, which would indicate which bank is giving you the problem, but the problem would not be the O2 sensor. It is just telling you that there is more oxygen present than normal because of unburned fuel from a misfire. Yes, it does sound like you have a problem with plug wires breaking down under load. I would replace them and the plugs, if you haven't done a tuneup recently (last 30K). Also put some injector cleaner in the tank, like Berryman or some equivilant.

 

I'm having the same issue with my 99 but there are no codes nor does it backfire just rough idle and bucks at highway speed some times not always. I have been told it could be the tps but do not want to chase parts. I changed the fuel filter and I have better pick up and not as many bucking motions on highway. At first it was only climbing hills but it started doing it on flat ground. Has any one else had theis problem. I do have the flex fuel 3.0 engine

 

I am also suffering from my Ranger.

 

Do a complete check on the electrical and fuel systems.
Even a small hicup from the engine will cause this sensation.
Plugs, wires, coils, grounds, everything.
Even a dirty air filter can cause this.