Why does my 3000GT misfire heavily?

Tiny
JOEYH_19
  • MEMBER
  • 1997 MITSUBISHI 3000GT
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 187,000 MILES
I have a 3000gt and it misfires really bad at low rpms and sometimes complete dies on take off. I have replaced rotor button plugs and spark plug wires, I have tried everything to the point I give up, it all started when I was trying to find a small misfire when I accidentally unplugged two wires at the same time and started the car. Sometimes when I have cylinder 3 spark plug wire plugged in half way it will run fine for a while and then starts all over again. When cylinder 3 plug wire is plugged in all the way it wont run at all. Really wish I could find out this problem cause im lookin to sell it soon and I dont want to lose money over this problem.
Tuesday, November 29th, 2011 AT 11:16 PM

13 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Check the sparkplug, compression and injector for cylinder no.3-start here
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Tuesday, November 29th, 2011 AT 11:26 PM
Tiny
JOEYH_19
  • MEMBER
  • 12 POSTS
I switched the injectors and the spark plug is fine, the day before it started I ran outta gas and I could smell a belt getting hot
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Tuesday, November 29th, 2011 AT 11:30 PM
Tiny
JOEYH_19
  • MEMBER
  • 12 POSTS
I switched injectors and I switched the spark plug on that cylinder but still nothing, the day before it happened I ran outta gas.
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Tuesday, November 29th, 2011 AT 11:31 PM
Tiny
RASMATAZ
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Check the fuel pressure with a gauge and also you need to identify where that smell is coming from-also you need to check the compression for that cylinder-This thing can end up with the crankshaft positioning sensor-
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Tuesday, November 29th, 2011 AT 11:33 PM
Tiny
JOEYH_19
  • MEMBER
  • 12 POSTS
Where would the crankshaft position sensor be located? And the cam sensor?
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Tuesday, November 29th, 2011 AT 11:36 PM
Tiny
JOEYH_19
  • MEMBER
  • 12 POSTS
Ive been trying to find this problem for about 6 months now, ive done everything to my knowledge to try and fix it.
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Tuesday, November 29th, 2011 AT 11:38 PM
Tiny
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  • MECHANIC
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Check the compression on cyl no.3 and comeback with the readings-
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Wednesday, November 30th, 2011 AT 12:18 AM
Tiny
JOEYH_19
  • MEMBER
  • 12 POSTS
The compression was within factory specs
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Wednesday, November 30th, 2011 AT 9:45 PM
Tiny
RASMATAZ
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Have you check and test the Cam and Crank sensors?
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-1
Wednesday, November 30th, 2011 AT 10:49 PM
Tiny
JOEYH_19
  • MEMBER
  • 12 POSTS
Where are they located? Wish I could find a diapgram of those cause they are the only ones I havent checked
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Thursday, December 1st, 2011 AT 12:23 AM
Tiny
RASMATAZ
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Camshaft Position Sensor (DOHC)In front of left camshaft, near sprocket.
Camshaft Position Sensor (SOHC)Inside distributor assembly.
Crankshaft Position Sensor (DOHC)On vibration damper. And
Crankshaft Position Sensor (SOHC)On vibration damper.
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Thursday, December 1st, 2011 AT 2:12 AM
Tiny
JOEYH_19
  • MEMBER
  • 12 POSTS
I checked all of those and they are good, is it possible I have a bad fuel pump? I mean itll run if I give it a lil gas but when I punch it, it will bog down like its outta gas
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Monday, December 5th, 2011 AT 7:32 PM
Tiny
RASMATAZ
  • MECHANIC
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Check the fuel pressure if its within specs to rule out the fuel pump
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Monday, December 5th, 2011 AT 11:25 PM

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