Need help troubleshooting strange miss.

[TwistedMunky]

To start out have been watching this sho for a long time. It went up for sale and i jumped on it. Previous owner was troubleshooting a no start problem, The local SHO garage charged them $250 to change the cam sensor. This didn't fix it he told them it would cost $1200 to change the crank sensor. The parked it up on a cement slab for 7 years before I bought it. That weekend I bought every thing for the front 60K and did it. I changed every thing that the shophoenix site said. Then for the **** of it I did the clutch, pressure plate, rear main, carriage plate, Both o2's , both temp sensors. The car has 110k miles on it. It has been running ruffer lately and has a leak in the exhaust. I was checking fluids in my brothers 94 "I maintain 6 sho's" and saw how smooth it ran. Went to look at mine since its almost acting like a miss i couldn't hear because the exhaust. when the starts up it revs up to about 1500rpms for about 20 sec. then drops to 1k. The cooling fan will be running for the 20 secs then shuts off. The temps have been running normal. I misted the motor to see if any of the wires were broken. Nothing jumped out so I was curios and unplugged one of the wires from the coil pack and placed it aside. No check engine lights or codes. The car does smell rich and I have a gutted y-pipe. So whats the best way to tell what cylinder is missing if the car doesn't see anything wrong with a wire missing?

 

[TwistedMunky]

I forgot to mention that I have owned 3 shos and have done 6 60K service's and have done the one clutch.

 

[e_clouser]

Any codes??

 

[TwistedMunky]

Let the car warm up, and ran codes I got a 11 and a 9 for cylinder check. So the car sees nothing wrong. I forgot to mention my gas mileage has dropped to around 11 mpg. I would think o2s but I changed them with known good ones. I do have access to a full shop if I need it. Also I haven't erased any codes. When I pulled the one plug wire last night it should have thrown something?

 

[frosho]

A bad or disconnected wire won't throw a CEL. It is WAY down on power, or does it feel more like an occasional miss? Is anything funny happening with the tachometer (i.e. reading low)?

 

[TwistedMunky]

The tach seems to read high. I normally shift at 2500 just by sound. I have been looking down and seeing i am shifting around 4K now at the same sound. As far as power i have never had this car to 100 percent it always had a problem somewhere. My old 91 had more miles and didn't have a y pipe it did seem to have more get up and go. not sure how fast a 2008 wrx is but im just slightly faster with him shifting at 5K and me at 7K. Its a steady miss. when doing the cylinder test it seemed one cylinder felt much different then the rest. Does any one know the pattern it uses to shut off the cylinders?

 

[hawkeye18]

Misfires (or apparent misfires) are caused by (in descending order of probability):

1: Plugs
2: Wires
3: DIS
4: Cam sensor
5: Negative ground for ECU at battery (the little wire, had a miss on my 95 that took two months to track down to it - it was frayed to two strands!)
6: Coil pack (rarely do they fail without it being pretty obvious that it's the culprit)

As far as the cylinder balance test, obviously you know how to enter it - but what you may not know is that after it finishes, if you blip the throttle again, it will initiate the test again - but with tighter parameters. If you do it a third time, it will tighten up the parameters even more - I think anything more than a 2% variance will trip a code? It might be 5%, but it's pretty twitchy at that third stage. A fourth time doesn't change the parameters. So try the balance test again, but run it 2 or 3 times in a row.