97 Ranger Bucking & Check Engine Light On

I have a 97 Ranger XLT 4x4, 4.0 6 cylinder with 118k miles. The engine has been running rough and often "bucks" while driving. The check engine light is on full time. Any ideas what might be wrong?

Reply to
NHYankBoy
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Pull codes and tell us which ones come up.

If you look along the bottom of the dashboard, in the vicinity of where your left leg rests while driving, or perhaps just to the right of the steering column -- different vehicles move the location around, but all have it along the bottom of the dash -- you will find a data port connector that is clearly identified as a test port.

Go to AutoZone, they will either connect the scan tool and pull codes for you, or give you the scan tool to use in the parking lot to pull the codes yourself. If you want to drive a different car to AutoZone, they will sell you the scan tool, and you take it home. When you are finished, you bring the tool back for a full refund, making the use of the tool free.

The tool simply plugs into the data port, and you follow the directions. Reset the codes and fix the trouble. AutoZone hopes you buy the repair parts from them, this is why the let you use the tool for free.

Given the description of your problem, I expect you will find some sort of misfire -- broken plug wire, bad plug, something like that. But, DO NOT pick up any wrenches based on that guess, pull codes and fix what the truck is asking you to fix.

I like this site to diagnose the codes ...

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Reply to
Jeff Strickland

The code reader is the best route.

If the maintenance is upto date (plugs, filters and wires) check the MAP sensor. The problem on my '94 4.0L turned out to be a white powedery deposit on my MAP sensor. I used contact cleaner to remove the deposits. The truck ran like a top. Engine light went out. MPG increased and no more surging. Be very careful with the sensor. DO NOT use a brush or even touch the fine wires on the sensor.

Reply to
Clay

I live in the country in NH, and the closest Autozone is 20 miles away. So I relied on my local mechanic to diagnose the problem. Turns out I had a broken spark plug. Thanks for the input.

Reply to
NHYankBoy

You can buy a scan tool on ebay. It can be used on any car or truck made since 1996. Or, on your next trip into town you can get one at the auto parts store.

I live in the country in NH, and the closest Autozone is 20 miles away. So I relied on my local mechanic to diagnose the problem. Turns out I had a broken spark plug. Thanks for the input.

Reply to
Jeff Strickland

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