Irregular engin activities and engine codes

Can anyone help me with this?

For a few years now my car, a 97 dodge neon, has been doing 3 strange things.
- In summer it tends to overheat if the A/C is above level one when driving around town or up small hills.
- the check engine light comes on periodically, and when the key code is checked it says the issue is the oxygen sensor.
- the engine often revs oddly when parked or stopped, like when first turning it on or when stopped at a stoplight. When it is really bad, it bucks when driving sometimes when windy. But it hasn't done that in a while. It usually just revs really high and then sounds like it is about to cut out. It doesn't cut out, but sounds like it.

When I took the car in last for this problem (9/04), they wrote the following: "Check engine light on, idle fluctuates when at idle. Performed scan test. Code P0132, oxygen sensor shorted to voltage and P0134 oxygen sensor stays at center. Ran diagnostic, traced codes to faulty oxygen sensor and replaced with new part. Cleared codes and road tested. Idle is consistent now, idle concern may have been caused by bad oxygen sensor."

And life was good for a few months. Perfect. Lovely. Later that next spring, the check engine light was on again, it was starting to idly a bit oddly again, so I took it in. They checked it (check engine light had turned itself off by then) and told me to make sure the gas cap was closed securely and that it causes a lot of problems. It sounded strange since I always twist the gas cap two or three clicks as habit.

Any help would be greatly appreciated. :banghead:

look at your coolant its probably brown sludge due to the blown head gasket i see that one all the time on the neons the engine light is probably not related.

look at your coolant its probably brown sludge due to the blown head gasket i see that one all the time on the neons the engine light is probably not related.

If the head gasket is blown, would the factory tech have seen that and also wouldn't I have a cloud of white smoke following the car as it is driving down the road?

you have 2 o2 sensors the other may be bad now

you have 2 o2 sensors the other may be bad nowGenerally it's the upstream sensor.

my down is bad right now.

Generally it's the upstream sensor.

What is that and where is it located? How much from the dealership?

my down is bad right now.

Your down? Are you saying there is a down stream also?

Upstream is on the exhaust manifold and down is after the cat converter.

yep 2 of them som bitches

yep 2 of them som bitches

If the head gasket is blown, would the factory tech have seen that and also wouldn't I have a cloud of white smoke following the car as it is driving down the road?

Not necissarily. I blew a head gasket and didn't have white smoke. And the DEALERSHIP missed it. I realised the problem when i was replacing the spark plugs and noticed the oil. (and on a side note-it's bizare that the spark plug tubes are SO long in a Neon)

Also-running on a bad o2 sensor can do quite a bit of damage to your cars engine. Especially if you drive it frequently in stop and go traffic. I've been told that especially with Neons it's good to hit the freeway and blow some of that crap out of your engine. I don't know if that's really factual---but hey-it does give me a guilt free reason to take it to 75 on the freeway every now and then :)

Have you ever had a shop to or mention a need for an engine vac?

Thanks, I will check for the blown head gasket as well.

running no or bad 02's wont hurt your car. thats why mpp com and afx coms bypass them all togather. i left mine hangin there on my last r/t when i got my mpp com and full exhaust. the SENSOR is there to tell you any erregularities with you air/fuel mixture by kicking on the dummy light. the neons computer is designed to correct any of the air fuel issues on its own.(for the most part) it just senses when there is an issue so if there isnt an issue with your air/fuel you can bounce the sensor down the street.

now someone is proly gonna come on here and tell me that the computer uses the readings from the o2's to make the corrections to the a/f but i have personally learned that it will run just fine without the sensors.

but im not promoting it im just giving another point of view.

the irregular idle could be due to a vacum leak or a dieing forget what its called sensor it right next to your tps sensor and has the plunger on it