Question about 2003 Ford Thunderbird
On exceleration engine stumbles above 2000 rpm returns to normal. Engine analyzer picked cylinder #7 misfire. Changer coil with no results. changed all spark plugs also no help.
Posted by Anonymous on
Ford coil on plug systems are multi strike ignition (spark) under 1300 rpm then go to single strike a single cylinder misfire can be created by several things . #1 Test engine compression on a cranking engine compression it should be around 150 lbs but if gauge reads different COMPARE to other cylinders that work fine #2 check engine running compression this will be around 120 lbs then rev over 2000 rpm and check pressure drop again COMPARE to other cylinders that work fine. any drop would indicate valve train problems. #3 All internal engine is fine then external problems are present vacuum leaks and or fuel injection volume is low.
Posted on Jul 23, 2014
It could be carbon deposits on valve seats keeping valves from totally closing. You can try getting you a can of motorcraft PM3 top end engine cleaner and get engine up to operating temp then remove one of the small vacuum lines from the intake and draw the contents of the can slowly into the engine.After you have drawn in the contents shut engine off and let it soak for about 45 minutes then crank it back up and let it run until it clears. Now it will smoke like a forrest fire while you are doing this so don't be alarmed,just tell the neighbors you are spraying for mosqitos.This may cure the problem. If not you may be looking at a valve job.
This can be verified with a compression test if this is what is causing it.
Posted on Feb 05, 2009
havent a clue here ,one cylinder now another missing ,only one thing comes to mind here and thats the coil pack ,check the voltage across the battery with engine running at 1500rpm and if its higher than 15.5 volts of their abouts then the alternator regulator is playing up and this would cause problems with the coil pack or the ECU ,also the radio could blow and lots of bulbs.Other that this i would need to get my greasy hands on it and give the magic hammer treatment
Posted on Jan 02, 2010
SOURCE: diagram of spark plug
Check this for 4.6 or 5.4 sizes engine...
2004 Ford Expedition 4.6 liter V-8 VIN "W"
2004 Ford Expedition 5.4 liter SOHC V-8 VIN "L"
Hope this help (remember comment and rated this).
Posted on May 05, 2010
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Sep 15, 2014 | Cars & Trucks
Trouble Code: P0301
Cylinder No. 1, 2, 3 or 4 Misfire Detected
Trouble Code Conditions: Engine is running; atmospheric pressure, fuel level, battery voltage, engine speed, engine load are above minimal predetermined specifications; the engine is not in fuel cutoff and intake air temperature and coolant temperature are within normal operating ranges; there are no DTCs relating to ECT, CMP, CKP, MAP or IAT Sensor, to Crank rationality, to Crank Sensor Learn invalid, or to System Voltage. If total misfires detected are greater than 7% during the first 1000 rpm, or are over 3% after the first 1000 rpm, or are 25% during any 200 rpm with suspect cylinder misfire counter more than 80% and no other cylinder misfire counters above 80%, this DTC will set. The MIL will flash after first trip occurrence and will be steady after second trip.
Fuel system problems existErratic CMP or CKP Sensor signalsIgnition system problems existEngine mechanical problems existPCM has failed
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