Hey,
Well two weeks ago I had this problem with my Check Engine light, it kept coming on and then magically turning off, so i thought it was a faulty sensor, but that week I had gotten regular instead of premium gas, well it wasn't a faulty sensor and when I put premium back in the car it turned off and stayed off until this morning when I forgot and asked for regular not premium at Amoco, and the light has been on all day, does this happen to anyone else? Thanks

I'd be really interested to know what code it's throwing. The owner's manual calls for 87 octane, and our timing curve is very conservative for 9.6:1 compression to make up for it. There is no reason i can think of it should throw a code based on what gas you run.

The only time I used 91 octane, my motor blew. I think it was purely a coincedence but I only use 93 octane now. Maybe the 87 octane at your gas station is just crappy.

I had something similar happen. Only I always use Premium 92(93?) octane..

My CEL came on, and went off one morning, then the next day I went to Sacramento and it stayed on whole day. Knock on wood it hasn't been on since.

While we're on the subject, what is the recommended octane rating we should get as a 2gNT? I've been using 87; should I switch to 89 or 91? Would that help increase performance?

Thanks

I use nothing but 93 for daily driving; if I happen to hit the track it's on race gas.

I use 87 octane in my Avenger all the time. Usually it is Exxon, but sometimes it will not be. I get 89 once in a while, probabally like one every month or two. Runs fine for me. No CELs and no problems at all. I don't drive it very lightly either unless I am trying to save gas.


-Nate



________________
-98 Avenger I4 5spd
-ALL MOTOR build up in process
-Mods: AEM Front Big Brake Kit, AEM CAI, Bosal Header

Next Mods:
Bored Throttle Body, Ported Intake Manifold

If you are nonturbo I believe that you are just wasting money if you buy anything above 87 octane since the car is set up to run that on stock compression and everything. Any differences would purely be psychological. Just my .02

sonicbewm is right. 87 is all you need, 91 or 93 isn't gonna do a thing for your car. You only need that for a much higher compression or boosted car. I've used 87 since I've bought the car. Don't waste money!

>sonicbewm is right. 87 is all you need, 91 or 93 isn't gonna
>do a thing for your car. You only need that for a much
>higher compression or boosted car. I've used 87 since I've
>bought the car. Don't waste money!


I 110% agree.

our cars will throw a code if the gas cap is not put on securly, maybe its just a coincidence that you put in crappy gas, maybe the cap wasnt screwed on correctly and when you put the better gas in you tightened the cap all the way down. or not just a guess

i always put 93 octane in my nonturbo no matter what. when i bought it the car was using 87 and it ran crappy.. it runs a lot smoother on 93

I bet some of you have no idea what the difference is in high and low octane fuel , just that the higher the better. That is right sometimes depending on your engine. For those who don't really know, higher octane fuel just takes more energy to burn than low octane. It's more resistant to "preignition", which if you have a basically stock engine, especially a 420A with only boltons, you should only need low octane. Maybe try another gas station, cuz most places do put "extras" in their premium gas to get everybody to use it.
Just thank god it isn't $5 per gallon like over here!!


Black '98 GS auto
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Front & rear strut bars
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"our cars will throw a code if the gas cap is not put on securly, maybe its just a coincidence that you put in crappy gas, maybe the cap wasnt screwed on correctly and when you put the better gas in you tightened the cap all the way down. or not just a guess"

mcgyvr

Is right you guys just dont tighten the gas cap correctly or tight enough. You gotta turn it like 4-5 times. When I dont tighten it correctly I get the light maybe the same day or a day after I put gas in my car and I put unleaded, as soon as I get of the car I re-open the cap an make sure it is closed correctly and the light comes off a few hours later or the next day and doesnt come back on unless I do the same mistake.



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The same sort of thing was happening to me, and it ended up being the O2 sensor. The CEL would show up for a while then go away, then return. It started coming on more frequently and after I changed the O2 sensor it went away for good.

Autozone, if you have one in your area, will check the code for free and it takes five minutes. That would be the surest way to know what is alarming.

Thanks for all the replies guys... the error code that I got was from Jiffy lube and the code was P0134 - O2 Sensor Circuit No activity Detected (bank 1 - Sensor1) and in the Chilton's manual that code is Ho2 stays at center... what should I do now?? Are there any threads on how to change the sensor if it is the sensor, cause I know that it would be the heated one on the headers, right? Thanks again for the help

" Thanks for all the replies guys... the error code that I got was from Jiffy lube and the code was P0134 - O2 Sensor Circuit No activity Detected (bank 1 - Sensor1) and in the Chilton's manual that code is Ho2 stays at center... what should I do now?? Are there any threads on how to change the sensor if it is the sensor, cause I know that it would be the heated one on the headers, right? Thanks again for the help"

I found out this very same thing about my car last week at Autozone (My light has been going on and off for months now).

I bought the Bosch 02 Sensor (before catalytic converter) yesterday, along with some new Bosch Platinum 4's. I'm going to change the sensor tommorrow. I was actually on here looking for a write-up on how to take it off too. I've already been under the car, and the wiring of the sensor just unplugs from a plug easily, but the sensor itself, I heard, is hard to break loose from the exhaust. Anyone know what tool to use, and how hard it is to break the sensor loose?

Lord Khan,

Yeah I justy found out that it's the upstream o2 sensor thats malfunctioning so I guess I have to buy a new one, where do I buy one and how much are they? Also which one do I buy...

I just removed my whole exhaust and the second O2 sensor was the hardest to get off but the first one was easy. What you need to do is go buy a $3 bottle of Gunk Liquid Wrench and spray it right where the O2 sensor is. Let it soak over night then take a 19mm wrench and try real hard to get it off without stripping it.

well my mom's J30 gets a CEL when I floor that sucka cuz we fill that thing up with 89 octane. It clearly sez premium fuel only on the cluster but she insists to put the cheap stuff in it. I'm guessing it senses knock or detonation and turn the CEL on.

Try resetting your ecu you may have spoiled you car haha, like it's used to using high octane now so if you reset it it'll learn again. Just a theory...

I didn't use any kind of loosening agent, I got out early in the morning after my car sat all night and it came off pretty easy. I used a an open ended wrench and a short pipe sleeved over it as a cheater bar. I reached it from beneath rather easily and without jacking up the car. This was on a 97 RS. Make sure you use anti-seize compound on the threads of the new one so it will be easy to remove later on. Mine came in a little "kit" with the anti-seize stuff.