[CrA5H]

O.k, I've been having this problem for a while and I think I have located the source. The problem that is was having was i would all of a sudden have very choppy acceleration in all gears. I thought it was my aftermarket coil pack and wires so I switched to ford parts and it still gave me the problem. Then I tryed switching spark plugs and went with the copper cores and still no cure, but the other day I wanted to make sure everything was tight and I pushed the harness that goes from the car into the coil pack in alittle and it worked ! The car ran beautifully for 2 days and then gave me the problem again. So, at a gas station, I opened the hood, unplugged this harness, made sure the spark plug wires were tight and plugged it in again and it ran good for about 20 min and then back to crap. Does this sound like the harness is bad ? and if so, should I replace all my engine wires ?

 

[CrA5H]

anyone ?

 

[Grinder]

Did you push the coil connector into the coil pack or did you just wiggle the harness? To answer your question - No. Replacing the entire engine harness would be expensive overkill. If the coil control circuits are failing I'd expect some codes. If you are positive the wires to the coil being wiggled will allow the car to run better I'd cut the harness open with a razor blade and have a look. Inspect the pins in the connector and the pins on the coil pack.

 

[CrA5H]

Well at first, I just dis-connected it and then pushed it back in to factory spec. The harness clicked it normally and then it ran good for those 2 days, then back to crap. I then zip tied it to the coil pack but that did nothing so I cut the ties and unplugged it and plugged it back in and it ran fine for about half an hour. I picked up a new harness from the ford stealer for $40, its called the (pigtail harness) pn # 3U2Z14S411TNA. It has longer wires than the stock harness to reduce pull. Im going to solder it this weekend and I'll tell you if the problem is gone.

 

[CrA5H]

Well, installed the new harness and it ran awesome for a day and back to the same jerky/choppy acceleration. but it does it intermittently, what would you do next ? all the wires under the hood ? maybe a bad ECU ? I have no idea and am at my wits end !!!!!!

 

[CrA5H]

also, still whenever i unplug the harness and plug it back it its o.k for a while. what the hell can it be ???

 

[iroc34]

Well, its good you replaced the pigtail. It is a common problem. It is strange that if you plug and unplug it, It runs good and then goes back to crap. If your plugs are good and gapped right, and the wires are also good. Have you tried cleaning the Maf ?. It could be a tps. Does it happen at all positions with the acceleration, or just under wot. Also awhile back , there was another member with the same problems as yours. His battery and charging system was not in proper working condition. Check all connections for corrosion, get the charging system load checked. How old is the battery ?

 

[CrA5H]

just changed out the maf with a brand new one. The battery is a optimum red top and is about 3-4 years old. The connections look o.k. You said maybe the tps ? how do I check this ? And yes, when this problem occurs it happens in all gears more pronounced the higher the rpms are so if im at 2000 rpms you can feel it but very little and then if im at 4000 or higher, it bucks like a wild horse !

 

[iroc34]

What kind of mods do you have?. How many miles on the car ? As the rpms go up and its getting worse. Sounds like the coil breaking down. You can also try closing up the gap on the plugs . It really makes a difference on my car. But it is FI. The tps can be checked with a scanner. Or the old fashioned way with a VOM. And lastly, have you checked for vacuum leaks ? . The pcv system on these cars is another common source of frustration. And the dpfe , egr system is another if you are still running them.

EDIT : OK never mind , I looked at your profile. nice ride. With the JRSC on there what gap are you running the plugs at ? And I also assume it does have a tune. And all the EGR equipment is shut off ? So never mind on the dpfe. How much boost are you running ? Has the fuel pump been replaced ? Fuel Filter changed as scheduled ?

 

[CrA5H]

Well, I just changed the coil out and wires last month to ford racing cause i thought it was the aftermarket screamin demon coil pack and that didnt fix the problem. My spark plug gap is around .030 or .032, I forget, but its around that and I changed to the motorcraft copper cores last month as well cause everyone gave them great reviews for foci. I do have a custom sniper tune running about 9 lbs of boost max. The car just hit 100,000 miles and have had the fuel filter replaced a couple months ago but not the fuel pump. I was thinking of doing the fuel pump but then if the pump was going wouldn't it give me the problem all the time ? Thats what is killing me, why when I unplug the harness to the coil pack and plug it back in does the problem go away for a period of time ???? lol , so confusing !!!!!!

 

[CrA5H]

Thanks for the love as well, invested way too much in it to give up !

 

[iroc34]

Do you have a way to datalog ? I know that Tom will take a look at it even if he didn't tune It. Only other thing I can think of . How many miles on the SC. Could it be bleeding off . Not holding a steady boost. ?

 

[CrA5H]

I went down to the garage that tuned it and they gave me a code reader that they said to use the next time that my car does the problem. I'm going to drive it tomorrow and hopefully when and if it does it, i will pull a code from it and be able to tell what it is. The supercharger has around 80,000 miles on it but has never given me a problem and when its not giving me the problem i can almost redline the car with perfect smooth acceleration and boost. I have never heard or felt any out of the usual things while under boost. This problem occurs whether im at 2000 or 6500 rpms, just a lot worse like I said in the higher rpms, like im all of a sudden running on 3 cylinders. I'll let you know what happens tomorrow. Thank you again for helping me out on this !

 

[CrA5H]

P0136 - HO2S Sensor Circuit Malfunction (HO2S-12) The downstream HO2S sensor(s) are continuously checked for maximum and minimum voltages.
The test fails when the voltages fail to meet the calibrated limits. Pinched, shorted, and corroded wiring and pins.
Crossed sensor wires.
Exhaust leaks.
Contaminated or damaged sensor.



P0455 - EVAP Control System Leak Detected (No Purge Flow or Large Leak) The PCM monitors the complete EVAP control system for no purge flow,
the presence of a large fuel vapor leak or multiple small fuel vapor leaks. The system failure occurs when no purge flow (attributed to fuel vapor
blockages or restrictions), a large fuel vapor leak or multiple fuel vapor leaks are detected by the EVAP running loss monitor test with the engine
running (but not at idle). After-market EVAP hardware (such as fuel filler cap) non-conforming to required specifications
Disconnected or cracked fuel EVAP canister tube, EVAP canister purge outlet tube or EVAP return tube
EVAP canister purge valve stuck closed
Damaged EVAP canister
Damaged or missing fuel filler cap
Insufficient fuel filler cap installation
Loose fuel vapor hose/tube connections to EVAP system components
Blockages or restrictions in fuel vapor hoses/tubes (items also listed under disconnections or cracks)
Fuel vapor control valve tube assembly or fuel vapor vent valve assembly blocked
Canister vent (CV) solenoid stuck open
Mechanically inoperative fuel tank pressure (FTP) sensor
Check for audible vacuum noise or significant fuel odor in the engine compartment or near the EVAP canister and fuel tank.



P0457 - EVAP Control System Leak Detected (Fuel Filler Cap Loose/Off) A fuel tank pressure change greater than a minus (-) 7 inches of H 2 0 in 30
seconds has occurred after refueling; or there is excessive purge (fuel vapor) flow greater than 0.06 pounds per minute. Fuel filler cap not installed
on refueling (storing continuous memory DTC) and "check Fuel Cap" light may also be illuminated.
Fuel filler cap missing, loose or cross-threaded.
Check for missing fuel filler cap or integrity of the cap. If OK, clear continuous memory DTCs and re-initiate EVAP Emission Running Loss Monitor Drive
Cycle.

-So with these codes showing up ? I should have my o2 sensor changed and fuel system looked at ? Doesnt make sense with the harness but this is what codes it threw this morning.

 

[CrA5H]

also got this code when I went out for lunch. It feels like the car is getting flooded cause something is stuck open, a valve or something and then when it corrects itself, its back to normal. When it starts the choppy acceleration also it back fires a lot which I know is fuel thats not burned off, hence all the fuel codes.


P0442 - EVAP Control System Leak Detected (Small Leak) The PCM monitors the complete EVAP control system for presence of a small fuel vapor leak.
The system failure occurs when a fuel vapor leak from an opening as small as 1.016 mm (0.04 inch) is detected by the EVAP running loss monitor test.
After-market EVAP hardware (such as fuel filler cap) non-conforming to required specifications
Small holes or cuts in fuel vapor hoses/tubes
Canister vent solenoid stays partially open on closed command
Damaged, cross-threaded or loosely installed fuel filler cap
Loose fuel vapor hose/tube connections to EVAP system components
EVAP system component seals leaking (EVAP canister purge valve, fuel tank pressure sensor, canister vent solenoid, fuel vapor control valve tube
assembly or fuel vapor vent valve assembly)

 

[iroc34]

Well what I would do if it were me. Get a tune from Tom. He can get you straightened out on all those issues. The FI tune is awsome.

 

[CrA5H]

You think its the tune or something else mechanical ? Im def going to contact tom and send him my ecu but you think I need to address the code issues or is that all in the tune ?