Rough idle, loss power, cyliders misfire HELP!!! | Ford Explorer Forums - Serious Explorations

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Rough idle, loss power, cyliders misfire HELP!!!

Goose25

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January 17, 2009
Messages
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City, State
moon
Year, Model & Trim Level
2003 XLT
I’ve had several issues with my 2003 Ford Explorer (V8 4.6L) over the past year or two. I’m unsure if it’s caused by or related to: EGR valve, Wiring, O2 sensor, vacuum, injectors, PCM, ignition coils, or other….. I’ve included a time-line of what I believe may be relevant information needed to help troubleshoot my issues.

Would anyone have a suggestion as to the steps I need to take to try to resolve these issues? I prefer the cheaper DIY approach, if possible.



November 2013
- P0316 - Engine Misfire detected on start-up (first 1000 revolutions)
- P0405 – Exhaust gas recirculation sensor A circuit Low
- P0304 – cylinder 4 misfire
Had a mechanic change all spark plugs and coil pack on cylinder 4. Erased CEL codes. Also, my mechanic noticed that my alternator wasn’t pushing out enough amps. Moments later when they retested the alternator it was now pushing adequate amps. :confused:



December 2013
I had issues with the battery dying when left parked overnight or when parked for the weekend (without being used). In comparison, I could sometimes leave my truck parked for several days and battery would not drain out!? I replaced the battery, had the old one tested and they said it was still good.:confused:



Jan 2014 (166 839km)
I had a problem with my transmission (5R55), was told that a “Piston overdrive” was broken and replaced. The shop pulled and erased my codes as follows:
- B1600 Ignition Key Transponder signal not received
- P0405 – EGR A circuit Low
- P0732 - Gear 2 Incorrect Ratio
- P0735 - Incorrect Fifth Gear Ratio
- P0775 - Pressure Control Solenoid 'B' Malfunction
- P1783 - Transmission Over-Temperature Condition



May 2014
Again, truck continues to idle very rough, loss of power & Gas mileage = 245L/1245km.
Pulled & erased codes:
- P0306 – Cylinder 6 Misfire Detected
- P0316 - Misfire Detected On Startup First 1000 Revolutions
- P0405 - EGR A circuit Low



May 2014 – Dec 2015
I eventually had to replace the alternator, it died. I also tried seafoam (through the brake booster hose), No improvements.



Jan-21 2015
Experienced a sudden loss of power on the highway. It seemed like the more I pushed on the gas the more the engine felt like it was being flooded (80km/h floored). When stopped I couldn’t get the engine past 3800RPM. I cleaned the MAF sensor and pulled and erased these codes:
- P0307 - Cylinder 7 Misfire Detected
- P0316 - Misfire Detected On Startup First 1000 Revolutions
- P0300 - Random Misfire Detected
- P0060 - HO2S Heater Resistance Bank 2 Sensor 2
After erasing the codes and cleaning the MAF sensor, the truck ran great!!!!...... for about a week.



January 27 2015
Loss of power and rough idling returned.
Pulled the following codes:
- P0307 - Cylinder 7 Misfire Detected
- P0316 - Misfire Detected On Startup First 1000 Revolutions
- P0060 - HO2S Heater Resistance Bank 2 Sensor 2 (where is it located exactly?)



Also, My heater and A/C doesn't push as hot or as cold as it should, maybe a vacuum related issue? Also, transmission seems to be affected by whatever is causing these issues, Ive experienced irregular gear shifting when the truck is acting up.

Any suggestions?
:)
 



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What's the fuel pressure?
 






you noticed that your cops are failing slowly 1 by 1, why not replace them all? erasing the codes and hoping they will not show up doesn't help, next will be your catalytic converter which is way more expensive to repair.
accel cops are cheaper in amazon, last time I bought them they were at $25 a piece.
 






Basic engine problems like vacuum leaks can play hell with idle rpm, rpm stability, trans "feel", and various codes. The same computer that controls the engine also controls the trans. Get a proper computer diagnostic and see what turns up. I suspect a big vacuum leak that the computer is trying mightily to compensate for.
 






UPDATE: I found the source to my problem. I followed "number4's" advice and decided to bring it to a local garage to have them test the fuel pressure. Also, asked them to lift the truck and do a quick inspection of the cats to see if they sounded like they were falling apart. Fuel pressure tested good, and cats were rattle-free. They pulled the codes and detected a p0302, p0307, & p0060. Misfires codes had them look at the COPs. Upon visual inspection they found what seemed to be oil in the plug wells #2 & #7 . They cleaned them out and erased the codes and my truck hasn't had a misfire since (p0060 code is still present, though). I asked if they had inspected the other plug wells, and they did not:mad:. I'll guess I'll be doing that on my own.

I did some reading on this wonderful forum (here) and have discovered that it must have been coolant leaking from my intake manifold! Bingo!

I can't believe I've finally found the source to my troubles. Now how can i identify if its the actual intake manifold that is leaking, or the intake manifold gasket? where and what should i be looking for? Also, as mentioned I've experienced misfires on cylinders #2 , #4 , #6 , #7 which lead me to believe it must be leaking on both sides of the intake manifold. And finally, would this explain my heating/cooling issues (thermostat)?
 






if it's oil in the plug then it's your valve cover gasket. if you are loosing coolant or coolant in the plug wells then you have an intake manifold leak, usually you can check for stains near the transmission bellhousing.
 






That intake manifold can leak anywhere. The most common place is the thermostat housing on the driver's side of the engine, which causes coolant to run directly into the spark plug holes for cylinders 5-8 on that side. If you had coolant in spark plug holes on both sides of the engine, though, I can't think of anyplace else that would come from besides the intake manifold.

I'm no expert, just speaking from my own experience.
 






Bad Intake Manifold

I had the very same problem on my 07 F-150. P0307. #7 Spark plug tube was filling with coolant and coolant was running low. When I removed the intake manifold I noticed a broken piece where the aluminum crossover seats up to the base of the intake, by the thermostat. Most likely your crossover is plastic and cracked from the middle leaking to both sides. I purchased an aftermarket intake online for $245. Way cheaper than autopart stores quoted. Replaced it, cleaned out spark plug port with air and all is good again. I saved a ton. Be sure u have a torque wrench and some patience. Btw Ford quoted me $640 just for the manifold. Hate to think what labor would have been. Good Luck
 






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