Bad O2 sensor?

[maroon93limited]

Can a bad O2 sensor cause a bit of a surge? I've done the tune up routine, including the fuel filter which seemed to make a bit of a difference, but there is still a slight surge while accelerating. The 93 is fairly low mileage for the year, 168,000 km's (roughly 104,000 miles) but was mainly city driven before we bought it.
An O2 sensor for this thing is dirt cheap and I have one on the way, but if it doesn't fix the surging, what else should I be looking for?
The tranny seems to be a bit off as well, like when I turn the cruise on the engine will rev quite a bit before dropping back down to the RPM that I set the it at. Should I maybe be looking at a tranny flush as well? and I have checked the throttle cable and seems very tight.

Hopefully the O2 sensor improves mileage a bit, as this thing is in big block Dodge territory!

Thanks everyone.

 

[92exp4x4]

What do you mean by a surge while accelerating? Does the motor run at higher RPM with little movement of the vehicle? Does the motor hesitate off the line? I'm not sure exactly what you are describing.

Your truck being a 93, should have two O2 sensors. There should be one on each downpipe.

 

[YBCold]

surges are usually vacuum issures. like a bad vacuum hose or a upper intake manifold gasket. BTW i just replaced my o2 sensor it has fouling from too much fuel and looks like oil burnt onn. but its also the oldie and it looks like it had never seen the light of day

 

[maroon93limited]

By surging I mean it doesn't accelerate smoothly. If I had to describe it, it would feel like as I'm getting up to speed, with my left foot I'm lightly pressing the brake in a rythmic motion. It seemed to be way better after I changed the fuel filter, but it's back. Not as bad as before, but I can definetley feel it.
I'm changing the sensor tomorrow night at work and we'll see if it makes a difference, but a tranny flush is also on the menu as it "feels" off.
I'm also getting rid of the cat (I love living in Canada!) and putting on a better flowing muffler as I'm pretty sure that the cat is plugged solid. You can hear the stock intake over the exhaust even standing right near the tip.

I'm hoping it's nothing major as this thing is so damn nice and really low mileage for the year.

 

[maroon93limited]

And at the same time that I'm changing the sensor, I'll grab a can of ether and check for vacuum leaks.

 

[Currency]

Sounds like it could be injectors. But I would check for vacuum leaks first. As for the O2 sensor I believe Explorers have two, one before and one after the converters. Are you changing both of them or just one? Also is your check engine light on? If so did you pull the codes?

My CEL is on and its showing codes for the O2 sensors... Two different codes. I just hit 186k miles on mine and the O2 sensors are most likely stock ones

 

[2000StreetRod]

Stumbling?

What you're describing sounds similar to what I call "stumbling". It can happen when the mixture is too rich or too lean for the load on the engine. Usually at highway speeds the cause is too lean. This could be due to a bad O2 sensor but more often the sensor is reporting actual conditions to the PCM. Vacuum leaks are frequently the cause of a lean condition but usually result in an OBD DTC being recorded. Try cleaning the MAF sensor with MAF sensor cleaner. A dirty MAF sensor is very difficult for the PCM to detect.

Other possibilities are weak spark plugs, wires or coil, excessive EGR, noisy TPS, low fuel pressure, clogged fuel filter or injectors.

Have you read the diagnostic trouble codes to reduce the possibilities?

 

[maroon93limited]

I haven't checked the codes, mainly because I don't have a code reader. I do have access to one, so that will be on the agenda tonight.
The CEL has never come on, and the plugs, wires, fuel filter and air filter are all brand new.
I cleaned the MAF once, but will do it again just to be sure, and as for 2 O2 sensors, mine just has one before the cat. I think they were different up here in Canada.

 

[YBCold]

forgot to mention Disconnect your battery so the PCM gets used to you mods. leave it unhooked for about 15 mins then drive around the block. i also had similar issue with mine so im going to check the same things

 

[shaggymane]

The last O2 sensor I bought was 50$. 4$ is dirt cheap. 12$ is cheap. Where do you find dirt cheap O2 sensor's? Midnight auto supply? What's that saying? If I had your money I'd throw mine away.

Anyway, I never got around to testing mine when I was getting HEGO codes.
Just went ahead and bought one. Now it's sitting on the hutch since it wasn't the problem. Which brings me to: when Mr shorty responds to a O2 code thread he frequently asks about the FPR. Which was my problem.

Something about it's connector being half way down by the hot exhaust manifold kept me away from it. I read not to be probing the wires on the harness or it'll ruin the sensor. So how else do you test one? Guy at the auto parts store said clued me into all the sensors go back to the CPU so it's a matter of finding which pins belong to each sensor.

Bad O2 sensor question comes up a lot. Did a search for "how to test O2sensors, in the useful forum. "No results". Tried - test O2 sensor - Found this one by Glacier991.

http://www.explorerforum.com/forums/showthread.php?t=149917

I"m gonna have to read that.

 

[maroon93limited]

Seeing as how the last O2 sensor I bought was over $100 bucks, I thought $38 was pretty damn cheap.

On the subject of code readers, where's everyone getting theirs Stateside? Not many shadetree mechanics have them up here, they seem to be a lot more popular down there. I might have to invest in one.

 

[YBCold]

i think Autozone rents them. harbor freight has some. or just ask a neighbor one of them will have one

 

[shaggymane]

Seeing as how the last O2 sensor I bought was over $100 bucks, I thought $38 was pretty damn cheap.

On the subject of code readers, where's everyone getting theirs Stateside? Not many shadetree mechanics have them up here, they seem to be a lot more popular down there. I might have to invest in one.

You have a point there. Dirt cheap can be relative. Needed an Alt. $145.00 at the auto parts stores - yeesh. Called every salvage yard w/in 3o miles. Found one 25$ and no core. Yeah, that was dirt cheap.

I got one of these http://www.amazon.com/Equus-3145-Fo..._1?ie=UTF8&s=automotive&qid=1260594493&sr=1-1 based on Anime's recommendation. He's says they're good. And I liked the price. 24.99, add another penny of something and it qualifies for free shipping. took a full ten days for delivery though

It takes an OBD1 reader for these Gen 1's, think AZ doesn't do ODB1.
There's always the paper clip method and count the flashes.


Added the link to Glaciers thread in the other post