Engine Misfires on cylinders?

Tiny
PGARRETT422
  • MEMBER
  • 1998 FORD EXPEDITION
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 300,000 MILES
Hi, When I press my accelerator it seems like the gas is not getting to engine. The car doesn't move then all of a sudden it jerks forward. When I come to a red light, the car will start smoothly if I can coast down hill a bit first. If I am stopped going up hill, the car jerks forward about 5 seconds after I press the accelerator.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
MASTERTECHTIM
  • EXPERT
A few things come to mind like a bad mass air flow sensor or ignition skip. Is the check engine light on? If it is bring it to autozone, hey will scan it for free then give us the codes and we can go from there.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
GEAUXTIGERS
  • MEMBER
  • 1998 FORD EXPEDITION
  • V8
  • 2WD
  • AUTOMATIC
  • 145,000 MILES
The check engine light in my 1998 Ford Expedition, 5.4L engine, came on. The diagnosis was a restricted EGR flow. A mechanic friend suggested I just clean the ports connected to the EGR valve. Did that, had the check engine light reset and within 10 miles, it came back on. I then replaced the EGR valve and the DPFE sensor, again cleaned out all the connecting ports for carbon buildup. Check engine codes now say, mixture too lean in bank 1 and bank 2 and misfire in cylinder 1. I am going to change spark plugs and coils this weekend, but not sure that will solve all the problems.

My question, is this more likely a vacuum hose problem, given the lean mixture codes? If so, which hoses should I look at and what should I look for?The vehicle will sputter upon acceleration, but then respond normally. It idles rough and will sputter while cruising. It also has a terrible vibration at around 50 miles an hour. Any advice will be appreciated.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
BMRFIXIT
  • EXPERT
The check engine light in my 1998 Ford Expedition, 5.4L engine, came on. The diagnosis was a restricted EGR flow. A mechanic friend suggested I just clean the ports connected to the EGR valve. Did that, had the check engine light reset and within 10 miles, it came back on. I then replaced the EGR valve and the DPFE sensor, again cleaned out all the connecting ports for carbon buildup. Check engine codes now say, mixture too lean in bank 1 and bank 2 and misfire in cylinder 1. I am going to change spark plugs and coils this weekend, but not sure that will solve all the problems.

My question, is this more likely a vacuum hose problem, given the lean mixture codes? If so, which hoses should I look at and what should I look for?The vehicle will sputter upon acceleration, but then respond normally. It idles rough and will sputter while cruising. It also has a terrible vibration at around 50 miles an hour. Any advice will be appreciated.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
  • 1998 FORD EXPEDITION
  • 5.4L
  • V8
  • 4WD
  • AUTOMATIC
  • 240,000 MILES
A few weeks ago my vehicle started misfiring, my OBD scanner said cylinder three misfire, and two bad o2 sensors. I replaced all the coil packs, plugs, and the two downstream o2 sensors. I also went ahead and replaced the intake, plenum, throttle body and EGR gasket(s). It ran great for about a week then started missing again. No CEL but scanner said cylinder four misfire. So I replaced all the injectors and o-rings, and moved cylinder four coil pack to cylinder five. When it is cold it runs fine but when it warms up it starts to miss, every so often, and has multiple misses in a row, after switching the coil packs the next day the scanner said cylinder five miss, so I checked and changed that coil pack. Again ran fine when cold missed real bad when warm, and especially when accelerating. I changed out the MAF, fuel pump, fuel filter, throttle position sensor, and the vacuum is at a steady twenty, quick throttle bump and it goes to two, back up to twenty five to twenty seven, then back to a steady twenty. At this point I am not sure where to go from here, could it be the catalytic converters, EGR or coolant temperature sender?
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
I have had this happen in the past if someone tries to use anything other than Motorcraft brand spark plugs. I have personally had this problem in three different vehicles that was being caused by using Bosch spark plugs. For some reason these Fords just do not like them. You also have to check very carefully that nothing has leaked into the spark plug tube and none of the plugs got cracked during installation.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
I originally put in NGK plugs with a heat rating of five, a week later I changed it to Motocraft with a heat rating of two, it did not make any bit of a difference all the holes were clear of any fluids or debris and the NGK plugs looked as If the engine was running lean.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
It is easy enough to tell if it is running lean. Just use a scan tool and look at the long term adaptive data and see if the computer is trying to richen the mixture.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
You might want to do a compression test also.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
Bank 1 is at +5% at idle 0% at 2k, bank 2 is +8%at idle and +2% at 2k.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
Okay, that puts the lean question to bed.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
At this point I am not sure what I should check next or what else it might be. It is a very inconsistent miss/misses at idle then a constant miss when under load.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
As I responded earlier, you need to do a compression test.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
Alright I will first thing in the morning. What do I test If the compression is good?
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
Compression is as fallowed (dry test) 1. 155 2. 165 3. 155 4. 150 5. 160 6. 165 7. 145 8. 150
(Wet test) 1. 170 2. 185 3. 165 4. 165 5. 175 6. 180 7. 165 8. 170
All +/- 2
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
7 is a little low but I doubt that is your issue. You are going to have to somehow determine if it is spark of fuel that you are lacking. That may require using a lab scope.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
So you do not think it is a catalytic converter issue?
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
WRENCHTECH
  • EXPERT
Why would you suspect a catalytic converter? That is not a symptom of a plugged catalytic converter.
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
JOHN EAKINS
  • MEMBER
Was thinking a restricted exhaust system might cause the exhaust to build up in the cylinders and cause a miss
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)
Tiny
GENE6210
  • MEMBER
  • 1997 FORD EXPEDITION
  • V8
  • 2WD
  • AUTOMATIC
  • 197,000 MILES
1997 Ford Expedition has diagnostic code for misfire on Cylinder #3. Changed sparkplug and coil, but code has not changed. What else could the problem be?
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Thursday, November 12th, 2020 AT 8:56 AM (Merged)

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