warm idle misfire

[bigchap]

Hi, i finally joined to try and get some help for a problem i cant run down on my ti, after i got it back from a transmission rebuild after the shop "updated" the transmission when they fixed a bad input shaft bushing, the updates eventually tore third gear to bits. A little while after getting it back my starter started acting up and not always engaging. So i proceeded to change the starter, i removed the intake to do this because i am not so great with small spaces, and while i was in there i found the plastic hose beside the engine block at the front was broken off on one of the branches and had not separated yet. So i also replaced all of the coolant lines, plastic fittings, water pump, and the valve that controls the water flow into the heater core in the cabin, i had about a week earlier changed the thermostat because i had to scrape ice off the inside of my windshield after driving about twenty minutes. after this i have not been able to fix the kind of rough idle or i would rather say it sounds like a misfire that occurs when it gets warmed up. To try to fix that i have replaced the spark plugs, spark plug wires, and coil (it was physically looking worse for wear). Most recently i tried the MAF because it will run better when it is unplugged, first i cleaned it and then i replaced it, though not with a $300 plus Bosch, no difference. In between the trips to the transmission shop i also replaced the cam shaft position sensor. I am stumped, my dad is stumped, and my regular engine mechanic does not like to work on imports. Sorry for this being so long but i wanted to give all of the information i could. Someone please help me, i just want my car back instead of driving my dads lancer oz rally, for awhile, i really miss it.

[cooljess76]

while the engine is idling, spray some brake cleaner on the intake boot and around the intake manifold. If you hear the engine rev up, you have a leak.

[bigchap]

I have tried that to make sure i got the intake back together without any leaks, but i wasnt spraying directly at the intake boot, i will try it again though, i replaced it before the transmission work. I forgot i also replaced the fuel filter before the camshaft position sensor.

[bigchap]

I tried spraying some ether around the intake boot this morning and i didn't any response from the engine, so i tried all the rest of the connections in the intake and all of the vacuum hoses and still didn't get anything, only time i did get any response was when i tested to make sure it was a good can of ether. I finally got to work on it when it was warm out and it missed as soon as i started it. I wonder if it could be something like a crankshaft sensor, o2 sensor, injector, or catalytic converter. I know the catalytic converter is bad (the welds are broke out of the ends of it) but i would like to get it running right before i replace that.

[bigchap]

I bought a code reader yesterday and when i hooked it up there were no codes and the only tests that had not ran were 02 sensors, catalytic converter and the fuel vapor system, still was idling rougher than all get out, it's starting to sound more like a really rough idle more than a miss to me, but dad still thinks it is a miss.

[xxxJohnBoyxxx]

Question: How does your car run under load like when you are driving it. Does it run good and pull normal. Does it only have this bad idle issue?

If it is only at idle maybe a CCV valve is blown and letting exvess crank gas in the intake at idle. That valve should only open during driving conditions so it would run good during normal driving and like crap at idle if it was completely blown out

Just a guess

[bigchap]

sorry its been awhile since i have checked this, it runs fine at over 1500 or so rpm. I had a couple of people tell me that the ecu was bad, so i found one for seventy bucks and am going to change it when i get the other one. if that doesn't fix it i will try that.

[xxxJohnBoyxxx]

You can change the DME but you will need the matching EWS and key chip if 1996 and up. Might be your CCV since it runs good above idle

[bigchap]

okay i found out what a ccv valve is and where it was located on realoem and took mine off, looked like it was broken from the underside when i took it off. car started up with the new one and ran kind of rough, really rough and then when i started it up a third time it started running smooth after a couple minutes. I think it probably is fixed but i need to grease my brake slides again and see if i can get the calipers broke loose again. The front drivers side caliper has stuck in the probably six months i have been tinkering on this car the passengers side does not look too good so after i get them loose or replaced again i will see if it is going to run good. thanks for the help.

[xxxJohnBoyxxx]

Originally Posted by bigchap

okay i found out what a ccv valve is and where it was located on realoem and took mine off, looked like it was broken from the underside when i took it off. car started up with the new one and ran kind of rough, really rough and then when i started it up a third time it started running smooth after a couple minutes. I think it probably is fixed but i need to grease my brake slides again and see if i can get the calipers broke loose again. The front drivers side caliper has stuck in the probably six months i have been tinkering on this car the passengers side does not look too good so after i get them loose or replaced again i will see if it is going to run good. thanks for the help.

Your cars computer will need some running time to adapt to the fixed CCV. It will need to lean out the fuel mixture since a bad CCV would be like a big vacuum leak.

[cooljess76]

Often times when a CCV goes bad, you could hear it hissing. Usually you could feel the air coming out of the bottom of it. Sometimes gunk will build up in the actual vent port on the back of the valve cover where the CCV hose attaches. This will also cause a misfire or a rough idle. As JohnBoy said, it'll take a few miles for the ECU to adapt to the new CCV. Your car logs data from the engine's running conditions to perform more efficiently.