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    Strange high idle

    My TC has been doing this strange idle thing for a couple days now. every now and then, the idle will go way up, but only if the engine is hot, and if i turn it off and back on, it's fine. When I'm driving, it feels like the cruise control kicks in, but I don't have ccruise control controls, since I have a Grant GT steering wheel. Ideas?

    "No other man-made device since the shields and lances of the ancient knights fulfills a man's ego like an automobile." -Sir William

    2011 Lincoln Town Car Signature Limited- Black on black, ADTR sway bars, 19" Mustang GT rims, Heinous rear control arms, dual exhaust with Flowmaster 10 series mufflers. MHS Stage 2 heads/cams, 80mm MAF, 75mm BBK throttle body, Accufab plenum, Stainless Works long tube headers, Ford Racing 24# injectors. ADTR T56 swap with Hurst shifter. 264HP/298TQ at the rear wheels.

    #2
    Mine does a similar thing once it has warmed up .. when I place it in park, the RPMs sound like they shoot up to 2000 or so, and it just idles high like that when it is warm .. restarting it usually settles it down.

    Comment


      #3
      Bad TPS can do this, so can a stuck IAC.
      86 Lincoln Town Car (Galactica).
      5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

      91 Lincoln Mark VII LSC grandpa spec white and cranberry

      1984 Lincoln Continental TurboDiesel - rolls coal

      Originally posted by phayzer5
      I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

      Comment


        #4
        yeah, tap on the IAC with a screwdriver handle and see if it helps.
        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

        Comment


          #5
          How much do the IACs cost to replace? A lot of people seem to have trouble with these...

          "No other man-made device since the shields and lances of the ancient knights fulfills a man's ego like an automobile." -Sir William

          2011 Lincoln Town Car Signature Limited- Black on black, ADTR sway bars, 19" Mustang GT rims, Heinous rear control arms, dual exhaust with Flowmaster 10 series mufflers. MHS Stage 2 heads/cams, 80mm MAF, 75mm BBK throttle body, Accufab plenum, Stainless Works long tube headers, Ford Racing 24# injectors. ADTR T56 swap with Hurst shifter. 264HP/298TQ at the rear wheels.

          Comment


            #6
            I got a brand new one from the auto parts store for about 55.00. You can get one off of a used car at the junkyard, they are everywhere on so many Ford vehicles, but with those you don't know if it's a good one or not.

            Comment


              #7
              OK, I installed a new IAC valve today, and the car drove perfectly on the way home, not even a single hiccup. When I got home, I put the car in park and was gathering up a small amount of trash and around 30 seconds later, the RPMs shot sky high. I thought my foot was on the accelerator, but alas, it was not. I shut down the car, restarted it, and about 30 second later, the RPMs shot up. It idles perfectly, no hiccups or anything, but the RPM thing is puzzling me. Ideas, anyone?

              "No other man-made device since the shields and lances of the ancient knights fulfills a man's ego like an automobile." -Sir William

              2011 Lincoln Town Car Signature Limited- Black on black, ADTR sway bars, 19" Mustang GT rims, Heinous rear control arms, dual exhaust with Flowmaster 10 series mufflers. MHS Stage 2 heads/cams, 80mm MAF, 75mm BBK throttle body, Accufab plenum, Stainless Works long tube headers, Ford Racing 24# injectors. ADTR T56 swap with Hurst shifter. 264HP/298TQ at the rear wheels.

              Comment


                #8
                check the tps voltages
                clean the throttle body......it might be gummed up and sticking......lube the throttle cable too, i have seen these stick

                1986 lincoln towncar signature series. 5.0 HO with thumper performance ported e7 heads, 1.7 roller rockers, warm air intake, 65mm throttle body, 1/2" intake spacer, ported intakes, 3.73 rear with trac lock, 98-02 front brake conversion, 92-97 rear disc conversion, 1" rear swaybar, 1 3/16" front swaybar, 16" wheels and tires, loud ass stereo system, badass cb, best time to date 15.94 at 87 mph. lots of mods in the works 221.8 rwhp 278 rwt
                2006 Lincoln Town Car Signature. Stock for now
                1989 Ford F-250 4x4 much much more to come, sefi converted so far.
                1986 Toyota pickup with LSC wheels and 225/60/16 tires.
                2008 Hyundai Elantra future Revcon toad
                1987 TriBurner and 1986 Alaska stokers keeping me warm. (and some pesky oil heat)

                please be patient, rebuilding an empire!

                Comment


                  #9
                  If the connector on the TPS and IAC is going bad, it could also be cause some extra resistance and altering the signal. Next time it does that, unplug the IAC real fast and see if the idle drops back to normal. If it does, then it's either a second defective IAC, or the wiring is going bad. If not then it probably is something to do with the TPS.

                  I'll cya tomorrow at the coffee shop.
                  Last edited by Blaze86Vic; 09-11-2009, 08:41 AM.

                  Comment


                    #10
                    Replace the ATC sensor. Mine did the same thing. It was easy to replace. When the car idles high like that, unplug the act and see if it stops. Also, have you had any cold starting problems?

                    Comment


                      #11
                      No, the cold idle is usually fine. Occasionally, it gets lumpy at a cold idle, the RPMs will go up and down quickly and repeatedly. Driving it around, at least once or twice a day the RPMs seem to get "stuck" around 1500-2000 rpm, but they will go back down after around 20 seconds. It's puzzling the hell out of me.

                      "No other man-made device since the shields and lances of the ancient knights fulfills a man's ego like an automobile." -Sir William

                      2011 Lincoln Town Car Signature Limited- Black on black, ADTR sway bars, 19" Mustang GT rims, Heinous rear control arms, dual exhaust with Flowmaster 10 series mufflers. MHS Stage 2 heads/cams, 80mm MAF, 75mm BBK throttle body, Accufab plenum, Stainless Works long tube headers, Ford Racing 24# injectors. ADTR T56 swap with Hurst shifter. 264HP/298TQ at the rear wheels.

                      Comment


                        #12
                        my idle has been irratic too.it started today.the car revs and idles high in any gear.and in park, it will fluctuate between high and regular idle.i did rinse my engine this morning so i kind of think some water got somwhere it shouldnt have.I disconnected the IAC and it stopped idling irratically.you guys think it might be the problem?
                        Last edited by Jonsey; 09-28-2009, 01:48 AM.
                        sigpic-The Crown(Kodiak)1989,150K Miles,5.0LOpo,autolamps,slicktop,power windows and locks,yet still not good enough to be LX:confused:

                        Comment


                          #13
                          My car just shuts off if I unplug the IAC.

                          "No other man-made device since the shields and lances of the ancient knights fulfills a man's ego like an automobile." -Sir William

                          2011 Lincoln Town Car Signature Limited- Black on black, ADTR sway bars, 19" Mustang GT rims, Heinous rear control arms, dual exhaust with Flowmaster 10 series mufflers. MHS Stage 2 heads/cams, 80mm MAF, 75mm BBK throttle body, Accufab plenum, Stainless Works long tube headers, Ford Racing 24# injectors. ADTR T56 swap with Hurst shifter. 264HP/298TQ at the rear wheels.

                          Comment


                            #14
                            Water in the distributor cap, or bad wires that are leaky can do this. Water in a sensor, water in a plug, etc. Drive it a couple days and see if it doesn't fix itself. If it doesn't, I'd probably start pulling connectors apart, drying them with compressed air, and putting some dielectric grease back in to seal the water out. I have had my car completely refuse to run before, and I finally chased it to water in the ECM connector after a heavy rain. Wasn't even driving it at the time, no idea why it got so wet but it did.
                            86 Lincoln Town Car (Galactica).
                            5.0 HO, CompCams XE258,Scorpion 1.72 roller rockers, 3.55 K code rear, tow package, BHPerformance ported E7 heads, Tmoss Explorer intake, 65mm throttle body, Hedman 1 5/8" headers, 2.5" dual exhaust, ASP underdrive pulley

                            91 Lincoln Mark VII LSC grandpa spec white and cranberry

                            1984 Lincoln Continental TurboDiesel - rolls coal

                            Originally posted by phayzer5
                            I drive a Lincoln. I can't be bothered to shift like the peasants and rabble rousers

                            Comment

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