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    shudder/miss

    As some of you may remember my merc has had a slight miss that although I have replaced everthing I can think of continues undeterred. I have changed the plugs,wires,distributor,tfi,cap,rotor,and ignition coil. Other than that I have replaced the IAC, map, egr solenoid, fuel filter,tps and im sure theres more im not thinking of. This miss can sometimes be noticed on deceleration, at speeds between 65 and 75, and sometimes a constant bucking between 35-40 mph. I've checked with several mechanics and two ford garages and everyone thinks Im nuts. I also have 150 lbs compression on all 8 cylinders. I am really stumped and aggravated as this is making it close to impossible to take the car on a trip, due to the random miss at interstate speeds which is sometimes barely noticeable and other times feels like its going to kill the engine. Also while this isnt an everyday problem as I rarely need to go over 55 its still aggravating when I want to do any interstate driving. Id much rather find a solution and enjoy the 450 mile trip to SF as I did last year than be full of rage for 8 hours cuz my junk wont run right.
    Last edited by mercurygm88; 04-09-2012, 02:28 PM.
    2002 Mercury Grand Marquis LSE, Sylvania Zevo LED Headlights, MSD Blaster Coils, K&N Cold Air Intake, Dual Exhaust, 3.27's - Dally Driver

    1983 Lincoln Continental Mark VI, Smog Delete - Summer Cruiser



    #2
    I was wondering if you were still having problems or not. Have you checked your EGR vacuum solenoid? If you unplug the vacuum hose to your EGR valve does it still do this? I haven't been able to work on mine. I pulled 2 EGR vacuum solenoids from the local salvage yard in hopes that one will cure the same problems I'm having. If I unplug my EGR vacuum hose my symptoms go away. Not saying my situation is exactly the same as yours but it's worth another shot and round of testing.

    Matt

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      #3
      I tried that once before with no luck but I actually am still kinda leaning towards something egr related. When I first had this problem it would throw a code for the egr solenoid. I replaced it with a borg warner egr solenoid from Oreilly auto parts and the code went away immediately, and the hesitation/miss/shudder/aggravation/headache whatever you wanna call it went away for a day or two. Then it was back but it still isnt throwing a code. Im going to replace the vac line from the map to the intake and the one from the intake to the purge canister saturday as there the only vac lines I haven't replaced yet. Other than that I'm gonna change the trans fluid and filter it was last done at 55k miles in 05 and the car is now at 99100 miles so its well over its 30,000 change interval, besides those two ideas I've run out of things to try. Oh yeah that also reminds me 900 miles and I'll have a brand new car with zero miles x3 I'll have to take a pic of all those zeros on the dash. Hard to believe its 24 years old and hasn't hit 100k yet. Even odder that I've put almost 18000 miles on it since June 26, 2011, then theres the fact that it looks like a 30,000 mile car some people really take care of there stuff.
      2002 Mercury Grand Marquis LSE, Sylvania Zevo LED Headlights, MSD Blaster Coils, K&N Cold Air Intake, Dual Exhaust, 3.27's - Dally Driver

      1983 Lincoln Continental Mark VI, Smog Delete - Summer Cruiser


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        #4
        If you suspect its egr related, unplug the vacuum line going to it.
        1989 Grand Marquis LS
        flat black, 650 double pumper, random cam, hei, stealth intake, Police front springs, Wagon rear, Police rear bar, wagon front ,exploder wheels, 205/60-15 fronts 275/60-15 rears, 1 5/8" headers, 2.5" offroad x pipe, Eclipse front bucket seats, Custom floor shifter, 4.10 gears, aluminum driveshaft and daily driven. 16.77@83mph

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          #5
          Unplugged the vacuum line and it still does it every now and then but not nearly as often as before, so I imagine its related to this in some shape or form.
          2002 Mercury Grand Marquis LSE, Sylvania Zevo LED Headlights, MSD Blaster Coils, K&N Cold Air Intake, Dual Exhaust, 3.27's - Dally Driver

          1983 Lincoln Continental Mark VI, Smog Delete - Summer Cruiser


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            #6
            How did your vacuum line replacement go Saturday? Were you able to changed the transmission fluid?

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              #7
              Lousy vacuum lines made the 88 buck like crazy when I got it... good chance they are bad, but you have to remove the upper intake to replace them (MAP and purge)
              Pete ::::>>> resident LED addict and CFI defector LED bulb replacements
              'LTD HPP' 85 Vic (my rusty baby) '06 Honda Reflex 250cc 'Baileys' 91 Vic (faded cream puff) ClifFord 'ODB' 88 P72 (SOLD) '77 LTDII (RIP)
              sigpic
              85HPP's most noteworthy mods: CFI to SEFI conversion w/HO upperstuff headers & flowmasters P71 airbox Towncar seats LED dash light-show center console w/5 gauge package LED 3rd brake light 3G alternator mini starter washer/coolant bottle upgrade Towncar power trunk pull underhood fuse/relay box 16" HPP wheels - police swaybars w/poly rubbers - budget Alpine driven 10 speaker stereo

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                #8
                have you tried cappin off all vac lines(except fuel press regulator) going out from the upper intake plenum? even the brake booster and PCV? it might be a good way to start eliminating posible vac leak culprates.

                1981 Mercury Marquis Brougham 2-Door 302/ 5-speed -special blend (GMGT)
                1987 Lincoln Mark VII 5-speed (Errand runner)
                1989 Mercury Grand Marquis (Base Runner)
                2007 Lincoln Town Car Signature Limited (Hustlyn)
                2011 Ford Crown Victoria Police Interceptor (Down with O.P.P)

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                  #9
                  This sounds like what I am experiencing. I am getting a miss at 55 mph and higher speeds. Keep us posted on the progress. I am going to take my upper plenum off soon and change all of the vacuum lines. I have changed just about everything but the map sensor, and I am still getting it. My spark plugs are white almost like the car is running lean. Goes like a mad hornet when you stomp on it though, so I dunno. I agree it is pretty annoying though, especially on trips.

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                    #10
                    Join the club

                    Originally posted by whitemgm View Post
                    This sounds like what I am experiencing. I am getting a miss at 55 mph and higher speeds. Keep us posted on the progress. I am going to take my upper plenum off soon and change all of the vacuum lines. I have changed just about everything but the map sensor, and I am still getting it. My spark plugs are white almost like the car is running lean. Goes like a mad hornet when you stomp on it though, so I dunno. I agree it is pretty annoying though, especially on trips.
                    I've had the same problem for over a year now. I'll cosolodate my posts to show you what I have done so far

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                      #11
                      OK here you go, Just to let you know what I have done based on my own experience and that of a dozen helpful souls from the forum:

                      Symptoms: bad miss , sputtering, jerking
                      occurs at light throttle the worst, but can feel it at all speeds.
                      also occurs on deceleration
                      Occurs when Cold or Hot, but slightly better when hot.
                      Car has good acceleration.
                      Pulled plugs twice after coming home, they are all wet like a rich
                      condition. Not real wet but wet


                      Things Done Already

                      Checked PCM Codes - shows no error codes. Only code 11
                      Checked battery voltage 12.5-OK
                      checked charging voltage- 14.5 OK
                      Checked coil input Voltage 12.5 OK
                      Checked coil resistance , was iffy so changed Coil,
                      Checked Base Timing -right @ 10 deg with spout disconnected
                      Checked Timing –advances normally with spout connected
                      checked compression – 145 +- 5 all cylinders,
                      checked vacuum 20 - 24 – OK,
                      cleaned Throttle Body
                      cleaned IAC (helped Idle but not much else)

                      Checked Manifold Air Temperature Sensor –Resistance correct with good transition when engine heats up

                      Checked Coolant Temperature Sensor –Resistance correct with good transition when engine heats up

                      EGR - vacuum tested and cleaned, also tried running with EGR capped off, Checked EGR sensor - voltage within specs with smooth transition.

                      reseated salt and pepper shaker connectors, and all sensor connectors

                      removed and cleaned all ground and power connections in engine compartment, Including ECM Ground

                      removed and reseated computer connector

                      checked fuel pressure 35-40 and fuel clear / clean – OK, Fuel pressure holds fine after engine is shut off

                      checked (listened to) all the fuel injectors I could get at 6 out of 8 sounded fine but couldn’t reach the 2 deep under the manifold- I don’t think it is actually an injector problem since the condition of all the spark plugs is the same. Maybe something controlling in injector dwell / Timing

                      Disconnected the Air Pump (removed the Belt) Ran car around to see if the computer would learn anything new. Still ran like crap. Computer knew right away that the Pump was disconnected. Code reader came up with 94 and 44 which are both Thermactor pump errors – reconnected pump back to code 11 on the PCM


                      CHANGED:

                      Plugs , Cap, Rotor, and Wires (all twice) currently has Ford racing wires
                      with standard copper plugs

                      PCV Valve, Screen and Grommet

                      Ignition Coil

                      Changed distributor complete with Ignition control module, and PIP sensor

                      changed throttle position sensor & set - resistance is within specs with smooth transition,

                      Changed MAP Sensor – No Difference

                      Replaced some burned harness wires to the WOT relay, and replaced relay

                      Seafoamed engine and ran 2 bottles of injector cleaner in gas.

                      Made sure and reset computer and gave it time to learn after changes

                      Removed upper intake and changed every fuel and Vacuum line in the engine compartment


                      Items I did not change or check, and Why:

                      Engine computer – Last resort also it seems to report proper error codes when I disconnect things otherwise reports code 11

                      Engine thermostat – Condition exists with engine either hot or cold and everything seems to heat normally- can’t see a reason to change the thermostat

                      Oxygen sensors – Computer should only look at them after warm up, and Condition exists with engine either hot or cold also I couldn't get at the connectors. I can now since I removed the upper intake, I also extended the wires so I could get at them later

                      Did not change the fuel filter because the lines under the car are so bad, I thought I might open up a can of worms – Also Fuel pressure was between 35 and 40 and fuel was clear as water and smelled fine.

                      I am going to change the speed density sensor because it is only 15 bucks but I haven't done it yet.

                      Bear in mind this is an older car and yours seems to be running lean not rich. If your car has a Mass Air sensor instead of a speed density based system , that sensor can cause all kinds of problemsBest of luck to you

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