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help !!! bad miss

catfishon

catfishon

Member
i have an 04 roadking that started to miss bad at steady speeds .
its fine if accelerating but as soon as i leavles off it misses and backfires.
had it at the dealer today and he said intake leak . but a hundred dollers later and new seals it still does the same thing. i put new plugs in and helped for a short time but never was great. also noticed rear plug had black carbon or something on it after only 35 miles. they also hooked it up to a tester and it showed no codes and fuel pressure was right on .
any ideas where to start now ? dont want to pay 100 bucks an hour when they have no idea whats wrong. should also add i have stage 1 with a tfi tuner . i took it off after trying everything else but still the same.
 
Was the TFI installed or removed when you saw the New rear plug having carbon on it. Has the fuel mileage gone down hill big time. Can you smell, see or sense a "rich" mixture at idle.
Is the bike hard to start (or harder than normal to start) when Hot? Does the bike backfire when you chop the throttle at high RPM. Did taking off the TFI, improve or make worse the situation.

Your sure there are no codes? You can check yourself using a WOW test. What was your fuel pressure in PSI when you checked it.
 
they checked the pressure at dealer , i saw it but dont remember, think it was 6 or 16 . they just said it was right on.
the tfi was installed but i unhooked the ground wire to it with new plugs. then latter hooked ground back up and the red pod light stayed on all the time , then took it compleatly off bike and still missed. it has all power and no miss at all if i accell, even with full thottle .
starts fine and runs better befor it warms up. front plug looked fine.
seems like it might be useing more fuel but didnt really ride it enough to know .
 
Don't know if your doing the work yourself but you may want to sweep the throttle position sensor (TPS) with a quality meter. It could have a bad spot right in the cruise range area that you would never see at WOT, idle or starting. And it may not be bad enough to throw a code.

May try riding the bike under the conditions where it will miss and try to force a code to log. Have you checked for them yourself.

Use this to read codes=>http://www.hdtimeline.com/archive/index.php/t-728.html
 
Others will chime in with good tips. I'm sure you will get the info you need to iron out the problem.
 
well i tried about all i can think of . drained gas and put new in. rode it a good while in the area it misses trying to get a code . NONE
i couldnt find how to test plug wires so i didnt do that. but it seems it would still miss during excell ? also when at idle i can hear it not firing for a second or too . sounds like old tractors do .
but when i hit throtle its all right there like it should be ?
guess its back to the dealer ,dont know what else to do ?
 
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