’91 Ranger Oxygen Sensor Problems?

I got a ’91 Ranger and my Check Engine light has been on for a while, and my gas mileage has decreased considerably, along with rough idleing and such. From what I’ve read, I think it could be the O2 Sensor. Any help is greatly appreciated. Thanks.

Have someone run the codes. That should help pinpoint your problems.

It could also be an EGR related problem, fuel injectors, or fuel injector pressure regulator.

A cracked/broken vacuum line can do it also.

First step is to pull the codes. Do it yourself places like bumper to bumper will sometimes “rent” you the Scantool to pull the codes. It requires a refundable deposit. Often times they rent is to you at no charge because the theory is you’ll buy parts from them.

Once you find out the codes, they can be cross referenced in the manuals provided (or if you want to, just PM me & I’ll look them up for you). My own opinion is that the code is merely a guideline, just cause you have a code doesn’t mean the sensor it points to needs replace.

If your code is for an O2 sensor, it doesn’t really mean you need a new O2 sensor..

If your electrodes on your spark plugs are worn out & you’ve had a misfire in a cylinder it could send raw fuel down your exhaust pipes. The raw fuel could trip an O2 code when reality is you need plugs, wires or something else.

Isolate the root cause, it’ll save you money in the long run. I can’t even begin to tell you of the number of repair shops out there that look at age & miles, then say…well… needs grocery list of items to start with.. without first checking for root cause.
Good luck.

Check around too, there should be places that will scan your codes for free, I know autozone does that around here.

Oh and check to make sure you gas cap is on tight, A lot of check engine lights are triggered because of this.

Should I just call up a parts store and ask if they could do the diagnostic thing for free? My old mans got one but it doesnt fit my Ranger.

yup

The shops are closed Sunday so I’ll check monday. My engine seems to bog down when I lightly step on the gas when I am stopped, feels like it wants to kill.

Like you said, I might try changng sprak plug wires too.

Thanks guys!