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At the beginning of May, I received a P0302 (Cylinder #2 Misfire detected) while starting the car up. I cleared the CEL and a few days later received P0420 (Catalyst system efficiency below threshold (Bank #1)), which I cleared as well.
For almost two months I have received no CELs.
Then last Monday, I received a CEL once again while starting the car. I didn't get a chance to pull the code until the other day. I got a P0303 (Cylinder #3 Misfire detected) and a P0420 (Catalyst system efficiency below threshold (Bank #1)).
What would cause the #2 and #3 cylinders to misfire on startup only?
FYI: Plugs and wires should be good. I replaced the spark plugs w/ Autolite APP764 (double platinum) plugs and wires w/ Ford MotorSport wires.
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
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Joined: Jul 2001
Posts: 4,168
I am Canuckian
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I am Canuckian
Joined: Jul 2001
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I'd still be inclined to pull those 2 plugs and check their gap. Also could be bad wires. Sounds like you have a problem that goes away as the car warms up right? I know everything heats up in an engine but I'd look at things that function more properly when they are hot. i.e., plugs and O2 sensors and I'm sure more but they aren't coming to mind at the moment.
Green 96 mystique gs 4cyl mtx
16.9 in the 1/4 mile @102500 miles
95SE in Midnight Red MTX
MSDS headers and y-pipe
SVT exhaust
SVT UIM
Optimized se TB.
Full pre 98 SVT body kit
15.741 @ 87.73mph :)
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Originally posted by mbb41:
I'd still be inclined to pull those 2 plugs and check their gap.
When I got the first CEL, I pulled the plug and checked it. The plug looked fine and the gap was right on.
Originally posted by mbb41:
Also could be bad wires.
Although it is possible, it is improbable. The wires are less than a year old and are made by Ford Motorsport.
Any other opinions???
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
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Oh no sounds like another nightmare like the DPFE was to troublshoot. I'd better pay attention mind will be next?
Paul
wonder if there is a TSB to help get started, or ask ALEX, he may have something as to what's about to die? How about slight bit of oil from valve guides, then when the fire's hot enough the plug/mixture burns properly.
How about slightly dirty injectors or not rich enough mixture or the O2 sensor starting to get tired and not switching fast enough? If I could just remember where I read how the PCM and with what it decided was a misfire?
If I can remember where I read that George I'll chime back in
Paul
98 Mystique LS 2ea (07/97)(08/98)
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Hard-core CEG'er
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Hard-core CEG'er
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The most common problem for what you are describing is ignition. Plugs, wires, or coil pack. Even if you have nearly new parts, it would be wise to pull those two plugs for inspection and look over those two plug wires as well. I too have the Ford racing wires, but they have been getting some bad press from this forum lately. If you have your original wires it may not hurt to substitute them back in for those two cylinders. If you can find a known good coil pack and swap it that may help pin it down.
Injectors are another posibility. If you haven't run some injector cleaner through it receintly it would not hurt to give it a try.
The cat effeciency problem might go away if you can correct the misfire.
Jim Johnson
98 SVT
03 Escape Limited
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Proper testing of the coil pack? Sorta like trying to measure the voltage of a lightning stroke. Is there a tester for this type of coil pack or just plain old substitution? This is one definitely to keep in mind. Rahmel has another post going, similiar problem. Ended up being the coil. Both were on the same bank? The negative firing side, design problem??? Whoops getting ahead of myself, George hasn't actually fixed his yet.
Paul
Do shops still use the scopes. Probably the best way to tell degradation? Kinda an expensive tool?
Paul
98 Mystique LS 2ea (07/97)(08/98)
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Originally posted by F111D F:
Rahmel has another post going, similiar problem.
Actually, Rahmel's problem is a little bit different. His misfire occurs while the engine is running, mine only occurs on startup (not afterwards).
Originally posted by Big Jim:
Even if you have nearly new parts, it would be wise to pull those two plugs for inspection and look over those two plug wires as well.
As I said, I pulled the plug in cylinder #2 and it was fine. I will pull the plug for cylinder #3 soon...
96 Contour SE
Duratec V6 24-valve 2.5L ATX
108,000 mi.
Replaced: crankshaft w/ DMD, EGR valve (clogged), EVR, DPFE, PCV valve, evap emissions hose & tube (cracked), window regulator (broken), LH & RH PCV tubes, UIM gasket (leak), ignition coil
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George which test are you running to catch this.
TNX
Paul
Just one PID so you can do a continuous?
Paul
98 Mystique LS 2ea (07/97)(08/98)
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