My service engine soon light keeps going on and off. It'll be on for a few weeks, then randomly go off again for a couple weeks. The thing that turns it on is when I drive up this one hill (the plateau of the 52 between santee and clairemont for anyone in the San Diego area). Anyone know what might be causing this? I didn't know the light would shut itself off after it turned on. Right now it is off, and I've driven the hill twice without it turning back on. Anyone know where I can get it checked out if it comes back on? How much do shops usually charge to check that kinda thing out?

recent changes... replaced fuel filter and cabin air filter. I thought this would fix the problem but I guess it hasn't(I do get better gas mileage though )

Anyway, if anyone knows what this might mean, please let me know, Thanks!

 

I had the same issue on my 02 MCS and it turned out to be the pre-cat o2 sensor.

Had it replaced and check engine light has only come on once and I know it was related to a loose gas cap.

Get the code read to make sure, but my gut is telling me it's the o2 sensor.

Hope this helps.

 

I agree, I would bet its an o2 starting to go bad. I bought the car with the check engine light on. had a code for down stream o2 sensor. the light would go on and off daily, I even got it through inspection like that. Get it scanned to find out for sure. places like auto zone will scan it for free for you, or if you have a regular garage you go to they could as well. If it is the o2 sensor you can get one from a parts store for around $150-$200 I would recomend the NGK brand as I tried a bosch sensor that didnt work.

 

thanks! ill have to get it checked out. will they be able to tell me what the code was even if the light isn't on right now?

 

Yep. The car keeps error codes in memory even if the check engine light goes off. They can clear the memory once they connect the code reader