Intermittent Engine Misfire Under Load
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Driver School Candidate
Joined: Mar 2019
Posts: 1
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From: ontario
Intermittent Engine Misfire Under Load
Hello all, just looking for some advice on my 92’ LS400. About a year ago half the ignition coils (loss of power etc) went bad and I (stupidly) drove to my mechanic while car was running very rough; said mechanic changed all ignition coils, changed plugs, tune up + oil change etc and all was pretty good. However, ever since the coil change etc sometimes when I accelerate onto the highway the car misfires or jumps slightly, sometimes it is worse when accelerating on a hill - almost like it’s bucking.. Other than this intermittent issue car runs beautifully like a typical LS. Have asked mechanic when back in shop and he tried some injector cleaner which did nothing. Even tho it is not a major deal and the car drives great 95% of the time I would love for it to be back to 100% as I only just past the 200,000KM mark. I understand it could be a number of things but any advice is appreciated.. thanks in advance
Pole Position
Joined: Nov 2014
Posts: 3,254
Likes: 418
From: CALIFORNIA
Hello all, just looking for some advice on my 92’ LS400. About a year ago half the ignition coils (loss of power etc) went bad and I (stupidly) drove to my mechanic while car was running very rough; said mechanic changed all ignition coils, changed plugs, tune up + oil change etc and all was pretty good. However, ever since the coil change etc sometimes when I accelerate onto the highway the car misfires or jumps slightly, sometimes it is worse when accelerating on a hill - almost like it’s bucking.. Other than this intermittent issue car runs beautifully like a typical LS. Have asked mechanic when back in shop and he tried some injector cleaner which did nothing. Even tho it is not a major deal and the car drives great 95% of the time I would love for it to be back to 100% as I only just past the 200,000KM mark. I understand it could be a number of things but any advice is appreciated.. thanks in advance
Check resistance of spark plug wires.(27 year old wires....use OEM)
Water temperature sensor?
Check each fuel injector.
PCV valve, grommet and hoses (both banks)
Engine vacuum hoses..
Throttle body cleaning
Inspect timing belt for cracks.
Negative battery cable and grounds.
positive battery cable.
Old fuses (tarnished blade contacts)
Throttle position sensor?
thermostat...
gas tank cap or gasket
oil cap gasket
Air fuel meter.(Do Not use spray cleaner)
EGR valve gummed up?
idle air control valve.
caps and rotors? (Use OEM)
fuel pump?
fuel filters (tank and extermal)
fuel pump resistor
Last edited by YODAONE; Mar 7, 2019 at 07:46 PM.
CL Community Team
Joined: Aug 2011
Posts: 4,180
Likes: 1,008
From: Japan
Sounds like a simple high voltage leak to me.
How to find where it leaks? The video below shows some of those ways. Of course there are other better ways but those needs special equipments designed for EE engineers or technicians and those need some knowledge and skills. Those ways Eric does are simple and easy for average DIYers.
How to find where it leaks? The video below shows some of those ways. Of course there are other better ways but those needs special equipments designed for EE engineers or technicians and those need some knowledge and skills. Those ways Eric does are simple and easy for average DIYers.
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