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post #1 of 1 (permalink) Old 03-06-06, 03:28 PM Thread Starter
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help, eradic idle/unstable running

I have a '94 Probe 2.0, thing runs fine with 85k on it...except for one thing..

It's idle. WHen it starts on a cold day (like today, when it's only 25 degrees out), it'll idle high at like 2.5k (which is normal)..then AFTER it warms up, it'll be at it's normal approx of 800 RPM's, but if I kick the gas once, and put it to like 2k RPM's, it'll stay at 2K for awhile, then maybe move down slowly to 1.4k, then down to 800 again, but it takes like a duration of 4 seconds to move back to 800, and this is AFTER it's completely warmed up, and sometimes it just stalls...plain and simple, fluctuating idle until finally it just gives out...

My first impression would be the O2 sensor, I don't know if it's the O2 sensor, it could verywell be the mass air flow sensor, that's why I wanted to post something here before I go out and buy new parts for a car I barely use anymore.

There's one more thing, Due to a cat jam, I gutted the whole cat, it's just an empty tank in the middle of the exhaust (that leaks like a whore because the gasket got messed up and I couldn't put it back in).

The CEL (check engine light) comes on when I"m driving and putting continuous pressure on the engine (eg. holding it in 3rd at 5k RPM's for like 15 seconds), but 20 seconds afte rshifting into 4th, the CEL will shut off, it was store din the memory so I hooked it up to a computer and it gave me the codes for "too rich" or "too lean" (it can't tell... which)...

So I think it MIGHT be the rear O2 sensor because it's reading all the messed up emissions of having no Cat that it's messing things up, though I'm not sure, I'm also going to try to turn DOWN the idle, because my friend kept turning it up when it was stalling on me and I think what's happening is it goes up to like 1.1RPM's to idle and then the ECU kills the fuel injectors, and it falls back to 300 (barely on the verge of stalling), then the idle kicks it back up again and it's in a paradox where it ends up stalling (the fluctuating idle).

That's my diagnosis of it anyways, what are your guys' opinions (if this belongs in a different forum tell me, I already posted it in the probe forum but that seems to be not too active..)

It's rediculous, I don't even need to step on the gas to take off, it'll be idling at 2500 RPMs on a warmup of like 10 minutes, I just have to pull off the cluthc, but it's rediculous, I hate this problem :(

Any suggestions are thx

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