Chasing Misfire
Thread Starter
Instructor
Joined: Aug 2017
Posts: 246
Likes: 6
Chasing Misfire
Everything Mark Haibeck said, my car does. Stumbles when bogging up in rpm at 30mph in 3rd gear etc.
Here are things i have recently done...
Replaced ICM
Replaced coil
Replaced Opti
So what next? Those things were in need of repair so i am fine with it. So now, what are common things that cause misfires in thw 96 LT4?
Here are things i have recently done...
Replaced ICM
Replaced coil
Replaced Opti
So what next? Those things were in need of repair so i am fine with it. So now, what are common things that cause misfires in thw 96 LT4?
Racer
Joined: Apr 2018
Posts: 349
Likes: 55
Everything Mark Haibeck said, my car does. Stumbles when bogging up in rpm at 30mph in 3rd gear etc.
Here are things i have recently done...
Replaced ICM
Replaced coil
Replaced Opti
So what next? Those things were in need of repair so i am fine with it. So now, what are common things that cause misfires in thw 96 LT4?
Here are things i have recently done...
Replaced ICM
Replaced coil
Replaced Opti
So what next? Those things were in need of repair so i am fine with it. So now, what are common things that cause misfires in thw 96 LT4?
Thread Starter
Instructor
Joined: Aug 2017
Posts: 246
Likes: 6
Plugs and wires appear new also claimed by previous owner. I have ran 2 tanks of injector cleaner treated fuel this weekend.
i will pull plugs and inspect them myself.
All good suggestions. Keep em comming!
i will pull plugs and inspect them myself.
All good suggestions. Keep em comming!
Racer
Joined: Apr 2018
Posts: 349
Likes: 55
A friend with an LT1 Camaro had a misfiring under load issue, it turned out that one of his wires had been rubbing on a pulley, and that a few others were not totally seated on the plugs - so they were on, but not 'snapped'. Fixing the damaged wire and getting all the wires on (a daunting task in an F-body, there is no room at all) fixed the misfire. When you pull plugs, clean them, gap them, and when you go to reconnect them, use dielectric grease, no sense needing to second guess them. Also, the plug connections at the opti could be the same way, not totally snapped on. Worth checking.
Le Mans Master
Joined: Dec 2005
Posts: 8,552
Likes: 936
From: Communist Colorado
Yes, this is a KISS situation in my opinion. Just because the plug wires and plugs appear to look good or your going on the PO's word... really doesnt mean much.
You dont know if one of the wires was damaged during install... maybe pulled on where it shouldnt have been.... there are a few places on the even side of the engine that are VERY tight... Also, there is the possibility of a plug with a cracked ceramic section.... also very easy to do... getting the plug socket a bit crooked while tightening will crack it if not careful. Possibly 7 or 8 since theyre the harder ones to get to...And yes, that causes a miss.
I hate to say it, but most times an opti is pulled, plugs and wires should also be done while in there.
You dont know if one of the wires was damaged during install... maybe pulled on where it shouldnt have been.... there are a few places on the even side of the engine that are VERY tight... Also, there is the possibility of a plug with a cracked ceramic section.... also very easy to do... getting the plug socket a bit crooked while tightening will crack it if not careful. Possibly 7 or 8 since theyre the harder ones to get to...And yes, that causes a miss.
I hate to say it, but most times an opti is pulled, plugs and wires should also be done while in there.
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