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95 Impreza racecar
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Discussion Starter · #1 ·
I bought a 1996 legacy 2.2l for my mom, however I am yet to figure out it's horrible missfire issue, if I am on the gas easy with little to no load, or in neutral the car revs fine with no bogging seemingly, however once I put it in drive and start driving, you cannot go past 20-30% throttle without it bogging and misfiring. I already replaced the spark plugs, wires, air filter, timing belt, water pump when I got the car for her, (the issue was there before the timing belt) I did some tests and the o2 sensor was varying hugely in its output voltage, no idea if thats ormal but I had a new one laying around so I replaced it anyways. The problem is still there, whether its hot or cold. I just replaced the o2 sensor (in a foot of snow lol) and now it will even backfire every now and then. SOOO my only idea now is a clogged cat, it rattles like crazy and Ive heard a clogged cat could cause bogging, any way to test it? Also would a clogged cat be a cause for slightly more than usual exhaust smoke? Any help greatly appreciated, thankyou
 

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2000 2.5RS BRP RSTi
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That does sound like a Fuel filter issue. except how it rev's just fine. but everything else does seem like a fuel issue.

(friends nova had this issue)

Best way to test the "clogged Cat" idea honestly is to pop it off and take a look. i dont believe there is any other way. just start it. and see if it runs better. may have to get it into 4k rpms , as it enters loop mode there and will bypass any O2 sensor code.(that would be my guess)

but try a fuel filter as its cheap.
 

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MY01 2.5 rs Black
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Had a 2.2 at my shop recently with EXACTLY the same symptoms. Okay rev in neutral, not great, and would fall on it's face with any load applied. O2 sensors going nuts. It had been neglected for so long that the fuel rail itself was plugged up with crap on one bank. The car would end up seeing a lean condition from the front O2, and try to add injector pulse, which would cause the two injectors that weren't completely plugged to over-fuel... Replaced the filter, pulled the fuel rails and injectors and cleaned them all out, and it ran great afterward!
 

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95 Impreza racecar
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Discussion Starter · #6 ·
Had a 2.2 at my shop recently with EXACTLY the same symptoms. Okay rev in neutral, not great, and would fall on it's face with any load applied. O2 sensors going nuts. It had been neglected for so long that the fuel rail itself was plugged up with crap on one bank. The car would end up seeing a lean condition from the front O2, and try to add injector pulse, which would cause the two injectors that weren't completely plugged to over-fuel... Replaced the filter, pulled the fuel rails and injectors and cleaned them all out, and it ran great afterward!
Good info! Thankyou. Fuel filter helped a bit, still underpowered but no more backfiring, theres a couple inches of snow on the ground so it's hard to tell how much it's bogging and how much is wheel spin, what did you clean the fuel rail out with? Maybe I'll seafoam it? Cat rrattles so bad I feel like it cant be helping..
 

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95 Impreza racecar
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Discussion Starter · #11 ·
Update: spark plugs are properly gapped, I pulled the front cat off today and there was nothing inside of it? The honeycpmb was COMPLETLEY gone, I replaced the cat (thanks to tim) but it's still bogging, I am changing the thread title because I no longer believe it's totally a misfire, it is too inconsistent, but sometimes the car falls on its face before coming alive again and never really runs as strong as I think it could, my only other thought now is maybe the first cat failed clogging the second cat? It wasn't rattling any though. Anyone else have thoughts?
 

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'MURRICA!
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No cat left?! Guessing it was burned out then. EGT's too high, which would mean a lean condition. Which would also suggest that the above posts are correct in a "not-enough-fuel" way. Those symptoms really scream "Hey, I'm out of gas!"

Get a fuel pressure gauge and check the pressure. Could be clogged injectors, bad fuel pump, stuff gummed up in the lines or the rails... They sell fuel injector cleaner at wal-mart even, run some of that through the tank and see what happens.

A cat "rattling a lot" usually just means that a heat shield is loose which is no big deal.
 

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95 Impreza racecar
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Discussion Starter · #16 ·
Heat shield was a little loose but even worse the metal bands that usually hold the cat material together were just flopping around in there, might buy a can of seafoam today
 

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Having the same issue with my car. Replaced fuel filter, checked all plugs, replaced ENTIRE exhaust, ran about 3 bottles of gum-out, trying seafoam next. What is the easiest way to pull the injectors, and what am I looking for on them?
 

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95 1.8->2.2 GF
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Having the same issue with my car. Replaced fuel filter, checked all plugs, replaced ENTIRE exhaust, ran about 3 bottles of gum-out, trying seafoam next. What is the easiest way to pull the injectors, and what am I looking for on them?
Have you tried disconnecting the front O2 sensor? or the MAF? check the fuel pressure regulator too.

I am stumped.
 

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I have tried everything except for pulling the valve covers to check the spark plug tube gaskets. And I am not going to be able to do this because I don't have the equipment, time, or the space.

Also noticing that now that it is quite cold in northern Indiana, my car only has the hesitation if it has been running for an hour or more. I really don't understand what it could be.
 
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