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larrym larrym is offline
ASE Master Tech - 35 yrs
 
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Join Date: May 2001
Location: Sierra foothills, CA-usa
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Thumbs up another 3.2 misfire question - solved



UPDATE - dosed it with Techron - ran the car 100 miles today (4-12) - using same DME as when problem originally surfaced

- no more misfire - fingers crossed


maybe just a sticky injector

it's been a year since i got my 3.2 conversion running, much thanks to many related threads here - and it was quite delightfull once the initial issues were solved

now i have a new misfire problem that recently surfaced

- it did not do this for the first 1500 miles or so - it would previously pull like a train in 5th from 1500 rpm with gentle throttle input and never required shiftdown even on relatively steep grades- it was like having an automatic trans

now the thing "bucks" or misfires under low-rpm load in higher gears at mid-to-deep throttle - e.g. under 2200, 4th-5th, especially pulling up an incline - if i downshift it is OK

and it occasionally "hiccups" on an uphilll pull even in lower gears at higher rpm (i.e. 3000) - almost as if there is a momentary total electrical disconnect, like maybe a loose connector somewhere - but i've checked all the connections & found no problems

fwiw - it recently got a new cap, rotor & plugs after getting very wet during an August deluge and developing a really bad misfire (http://forums.pelicanparts.com/porsche-911-technical-forum/714211-misfire-after-storm.html), - it ran perfectly after that fix

until now - as described above

the still-oem wires & plug ends test OK per spec & show no cracks or nightime arcing

- i have 4 good DME's and have swapped one just to rule that out; also has new pump & filter, etc

and yes i have the Test Plan and have been thru all that stuff (search my other 3.2 posts)

here is a relevant thread:
http://forums.pelicanparts.com/porsche-911-technical-forum/719543-3-2-engine-jerking.html

?? any good ideas that are speciific to such a misfire??

? has it actually happened to you & what solved it?

TIA
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Last edited by larrym; 04-12-2014 at 09:26 PM.. Reason: UPDATE
Old 04-03-2014, 10:54 AM
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