mildmileage Posted February 23, 2017 Share Posted February 23, 2017 Hey everybody - first post on the site, I have a '96 Legacy with a bunch of miles on it that, for some reason, is getting awe full mileage. We recently picked it up and it seems to run great, we do/did have some issues with it though; - Every once in a while, it will do this very strange stutter thing, it seems to only do it when the engine is cold and when you are decelerating from about 50mph+, it will start stuttering really bad, like it's starving for fuel. But then, it will come out of it. Never get a CEL. Stuttering never lasts more then a minute or two. - When we first got the car, the thing had a starting issue, ended up being the coilpack (at least, that is what fixed it). The starting issue was really weird, it would turn over and cough, but that was it. Once you got it started though, it would be fine for the rest of the day. Air filter is fine, tire pressures are normal. The next thing I am going to look at is the spark plugs, throttle body, and PCV valve - did you experts have any other recommendations? What about a knock sensor? Shouldnt I get a CEL for that? -MM Link to comment Share on other sites More sharing options...
Das Ninjabot Posted February 23, 2017 Share Posted February 23, 2017 This sounds like an issue I had with a Camaro (don't judge!) that ended up being a bad o2 sensor. The hard starting was because it was running rich when cold, a new coil would give a stronger spark and mask the cold start problem. Link to comment Share on other sites More sharing options...
mildmileage Posted February 23, 2017 Author Share Posted February 23, 2017 This sounds like an issue I had with a Camaro (don't judge!) that ended up being a bad o2 sensor. The hard starting was because it was running rich when cold, a new coil would give a stronger spark and mask the cold start problem. Wouldn't you get a CEL for a bad O2 though? Link to comment Share on other sites More sharing options...
Das Ninjabot Posted February 23, 2017 Share Posted February 23, 2017 In my case I didn't throw a cel. It was not bad enough to trip the cel, but was bad enough to cause problems with mileage and cold starts. Not saying that this is your issue btw, just that it might be a possibility. Link to comment Share on other sites More sharing options...
95subiblu Posted February 23, 2017 Share Posted February 23, 2017 I'm on the same boat. Changed my o2 sensors, removed my cats, changed my pcv valve, intake mani gaskets, and coolant temp sensor and nothing has changed. My fuel pressure regulator seems to be good still and my maf is barely 6 years old so idk. Id say check your MAF, clean it even. Or, how many miles does your car have? Link to comment Share on other sites More sharing options...
Brighton96 Posted February 23, 2017 Share Posted February 23, 2017 +1 to bad O2 sensors, it may not throw codes but it sounds like they've been bad for a long enough time period that the car doesn't know to run lean or rich which will cause it to stall, not start, get horrible mpg, shudder etc etc. Link to comment Share on other sites More sharing options...
choover1101 Posted February 23, 2017 Share Posted February 23, 2017 Have you checked to see if you have a code? I took my cel bulb out to pass state inspection. Similar issues for me was a bad knock sensor. About 15 minutes with wobble extensions and some tape and I had it swapped out. Sent from my SAMSUNG-SGH-I747 using Tapatalk Link to comment Share on other sites More sharing options...
mildmileage Posted February 23, 2017 Author Share Posted February 23, 2017 Thanks everyone for the replies, after scanning the rig I found out the CEL bulb is burnt out/missing, and I misfire codes for cylinder 1, 2, and 3. The spark plugs, wires, and PCV looked original (and this car has 200k+ on it), plus the throttle plate was disgusting. I also cleaned the MAF sensor (with MAF sensor cleaner - I learned many a year ago that carb cleaner doesn't work for that.). Couldnt spot any vacuum leaks, sounds like if the issue persists I will be investigating 02 + knock sensor. thanks for all the replies guys. -MM Link to comment Share on other sites More sharing options...
30legacyl Posted February 25, 2017 Share Posted February 25, 2017 Are you sure the Injectors are all working properly? I had one going bad & acted up intermittently- then failed completely... Kinda sounds like some of the symptoms I saw before the total failure.... jm$.02 Link to comment Share on other sites More sharing options...
doublechaz Posted February 25, 2017 Share Posted February 25, 2017 It could run extrememly rich because of a failed injector not putting fuel in. The cylinder with no fuel will not have combution and all that oxygen will then go out the exhaust valve. The O2 sensor then says 'holy crap we're sooo lean, put way more fuel in!' One check you can do is use one of those infrared thermometers to check the exhaust temp for all four cylinders. If one has no fire you'll see it. If you have the 2.2 liter with single port heads it won't work so well, but you may still get an answer if you are careful. You can disconnect the electical connector to injectors while it's running one by one and watch for changes. You can do the same using proper tools with the spark plugs. Link to comment Share on other sites More sharing options...
RumbleRumble Posted February 26, 2017 Share Posted February 26, 2017 do a "tune up" first. Link to comment Share on other sites More sharing options...
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