20 Most Recent 1991 Ford Explorer Questions & Answers

1. Throttle control problems: A sticky throttle control or a malfunctioning throttle position sensor could be causing the high revs.
2. Ignition system issues: A faulty ignition module or spark plugs could cause the engine to run rich, causing high revs.
3. Vacuum leaks: A vacuum leak can cause the engine to run lean, leading to high revs. Check for any visible leaks in the vacuum lines and hoses.
4. Fuel system problems: A clogged fuel filter, a failing fuel pump, or a malfunctioning fuel pressure regulator could cause high revs.
5. EGR valve: A clogged or sticking EGR valve could cause the engine to rev high.

It's recommended to have a professional mechanic diagnose the issue using an OBD-II scanner to retrieve the error codes and perform a proper diagnosis. Based on the error codes and the symptoms, they can determine the root cause of the problem and recommend the necessary repairs.

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You should not drive a car if the check engine light comes on and you do not know what the problem is. In some cases the check engine light means a serious problem and I know could cost a lot of money to repair. Mine came on and cost $800 dollars to repair as I tried to drive it.

I had a 91 and don't remember a kill switch of any kind in it. What was the scenario when the vehicle died? May be able to guide you in the right direction.

talk with an auto electrician as there are now many alternators that are controlled by the ECM ( voltage regulator is in the ECM) 14.5 volts -14.38 volts is good voltage control so the problem may not be the regulator at all problem could be a shorting diode in the circuit or other problems not connected to either the alternator or regulator such as wiring shorting out , bad connections etc may even be an ECM problem

The catalytic converter or muffler maybe plugged up. This is based on the engine getting fuel and fire to the plugs. I would remove the 02 sensor ahead of the cat. and see if truck will start, be aware if it does start it will run rough. When the cat or muffler get blocked off it puts back pressure on the engine and thus not allow fuel into the cyl. to fire.

Check for blown head gasket if there is steam coming from the exhaust,also check that the theremostat is opening.

Check for vacume leaks and fix all that you find and if still does it check for codes...Could be several things causing this Mass Air sensor , Idle air control ......Most likely vac leaks or mass air .....Make sure air filter is clean

I sounds like you have a leaking fuel injector, is the engine misfiring?

Your truck has a resistor block that runs the fan control so if it totally fails it might work intermentently but I would start there replace the blower motor resistor block

yes it could cause the blinking red light.

Well call and price it between a garage and locksmith. If they are the same price. Use the locksmith, because he comes to you. You will have to get the truck to the garage, Tow bill..

On a 1990 Ford Explorer the engine block is cast iron, and the cylinder heads are aluminum .

Put the adjuster in last. That is how I do it. It should be no problem to spread the shoes far enough apart. Then adjust til it is a snug fit to get the drum back on.

Actually, it is pretty easy to do. remove the glove box assembly. the case cover is right there. remove the 2 heater hoses under the hood. remove the inside cover screws and the core unbolts and comes right out. It only pays 1.2 hours in a shop. And you don't have to mess with the A/C system.

The horn and rear defrost are on two different circuits. There will be a fuse for each. Most common problem on SUV,s for the rear defrost is a broken wire on the glass grid of the rear window. As for the horn,it could be caused by a bad horn/fuse/horn relay/horn pad/broken wiring. You need to disconnect the wire to the horn and use a test light to see if there is power at the horn when the horn button is pressed. If there is power, the horn is bad. If no power, any of the afore mentioned could be the problem

Broken clips that hold the window to track, damaged lift mechanism