Persistent Misfires! | Ford Escort Owners Association (FEOA)

Persistent Misfires!

Discussion in 'ZX2 1998-2004 2.0L DOHC' started by NickB, Oct 25, 2019.

  1. NickB

    NickB FEOA Member

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    Okay. 1999 zx2 5-speed 168k. No AC, no power anything. I have been bothered by this issue since last summer. I had a bunch of work done on the car ($1000+) new clutch, slave, master, CPS, main seal, resurface flywheel. It came back with a misfire on 2 and 3 P0302, P0303 and sometimes P0300 blinky cel. I had this before, but plugs and wires eliminated it years ago. I had the mechanic go over the car twice to find it- fuel trims good, good battery, new high end alternator, backprobe crank sensor, everything good. No vacuum leaks that I know of. Head gasket is good. Put it on his Verus and drove it for a week and concluded it wasn't misfiring. I gave up and just drive it. Had a idler pulley grenade itself at 50 mph and threw the timing belt back in June. Had it towed to a shop (was at the coast for the weekend and left it). Guy put a timing belt on it new pulleys. He compression tested it, came out fine (non interference engine vin-3). Still misfire codes. I flushed the radiator last spring. Put new plug wires, new Motorcraft plugs (the right ones fine wire) a couple.months ago. Didn't change. I'm putting good quality gas in and did a bottle of Techron injector cleaner on a 1/4 tank and it seemed to run 'better' but still misfires. Doesn't run hot, never overheated. Car has idled rough for years, but otherwise car runs fine other than hesitation off the line sometimes (1st gear only), and it does lose power in 3rd gear when merging onto onramps, but that's random. I clear codes, but they just come back. Seem to happen consisteny off idle after sitting st a light, or in 3rd gear going uphill or on hard acceleration I can feel it missing but almost unnoticeable. The only things I can think of is a throttle position sensor, invisible vacuum leak (I fixed one with the PCV years ago- had it smoke tested), bad coil module. Engine burns hardly any oil (maybe 1/4 qt. between 4500 mile changes, I never have to add oil). I am at a complete loss! Any help is appreciated.
  2. marclar

    marclar Moderator Staff Member

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    i believe there is a breather hose that runs from the block to the back of the intake, unless that is the hose you refer to. ford misfires are one of the hardest things to diagnose because the pcm doesn't give you any use able data.
  3. pextor

    pextor Moderator Staff Member

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    I believe 2 and 3 are on the same coil. I would throw a coil pack on it.
  4. NickB

    NickB FEOA Member

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    You're right that my scan tool doesn't give much data. I thought getting a expensive scan tool and using it to diagnose the issue better than my cheap one then returning it. The hose I mended was the pcv valve to the intake like you mentioned. I didn't replace that hose assembly because Ford wanted like $70 for it so I kept the tube and replaced the cracked rubber bits. I will check it again for leaks.
  5. NickB

    NickB FEOA Member

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    That was my next move since they're pretty inexpensive for even an OEM one on ebay. I will check the plugs to see if they're fouled somehow.
  6. 4cylinder

    4cylinder FEOA Member

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    if the coil does not fix this problem then report back. I have had to fix this before and the fix is far more sinister than a coil pack replacement
  7. Swift

    Swift FEOA Donator

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    4cylinder, spill it now I am curious
  8. NickB

    NickB FEOA Member

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    Uh oh. I don't like that word sinister. From experience that means major disassembly and $$$. What's the fix so can I prepare for it? Cylinder head? I heard this is not unheard of when the valves get excessive carbon buildup. Valve seats? I have never done a leak down. I thought I'd mention that the hesitation off the line happened after the clutch replacement...
    Thanks
  9. marclar

    marclar Moderator Staff Member

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    we have the ford ids scan tool here at my shop... still doesn't give any useful information. and it is the most un-userfriendly scan tool i've ever used. the good news though, is that i don't work on fords anymore!! im so happy
  10. NickB

    NickB FEOA Member

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    At least Ford gives you mode 6 days. I haven't figured out how to access it with my scanner. My 2002 Subaru Legacy is the same way. Very little usable diagnostic pid other than the basics. They have their own scanner Subaru Select tool with cartridges for different functions or systems. So unless you have a really expensive scan tool, you're going to be scratching your head.

    Anyway I picked up a new coil pack from Napa yesterday and will install it when I get to feeling better and report back. Hopefully that fixes it.
  11. NickB

    NickB FEOA Member

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    I picked up a coil from Napa yesterday and will install it as soon as I get over my cold so stand by!
  12. DrZX2

    DrZX2 FEOA Member

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    If the coil pack doesn’t fix the issue maybe check the injectors for clogs/bad spray patterns. Other than that check the simple stuff (air and fuel filter, clean throttle body, etc.). I find a lot of times with these cars it’s always the simplest thing that causes the biggest issues.
  13. NickB

    NickB FEOA Member

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    I installed the coil this afternoon and have driven it 20 miles or so and no code yet. Sometimes it will go a day or two without tripping the dlc. However, the idle is a little better. I discovered I need to put in a new thermostat since it takes forever to heat up. I can drive it for 15 minutes and it never gets over 150 degrees. Unless I'm sitting idling for 15 minutes the needle doesn't budge.
  14. NickB

    NickB FEOA Member

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    UPDATE I've been driving the car for a couple days now, and the check engine light came on once for p0303 cylinder 3 misfire. I cleared it Monday and it hasn't been back. I'll pull the plugs and check if they are fouled. I can tell it still has a rough idle though. Fingers crossed it doesn't come back! Next fix is the cooling system. My heater sucks, barely warm even when I let it idle and heat up to 203 F so I'm guessing a grungy heater core. I'll flush the whole system again with cleaner this weekend.
  15. NickB

    NickB FEOA Member

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    Misfires are back. I'd line to know what your fix is for this.
    Thanks
  16. 4cylinder

    4cylinder FEOA Member

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    here is what is wrong with the car i had to fix with this exact issue. The car ran decently and did most everything is was supposed to do. Even passed compression test

    oh noez 01.jpg oh noez 02.jpg
  17. NickB

    NickB FEOA Member

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    Oh man. Did it pass the leak down? Valves aren't supposed to be oblong. There's no way I'm pulling off the cylinder head to fix that. I did fix a couple vacuum leaks on the evap purge canister this weekend when I swapped the thermostat and flushed the cooling system. Idle is better. Still had the misfire. What did your spark plugs look like on those cylinders with the burned valves?

    Thanks!

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