What does a misfire feel like?
Racer
Joined: Jun 2005
Posts: 333
Likes: 1
From: Mendota Heights MN
Exactly -- just had this happen when I picked up my car from the dealer last night after replacing the lifters. Turns out they had cracked a spark plug, and it stumbled off idle, occasionally cutout at idle. Very noticable.
Melting Slicks
Joined: Mar 1999
Posts: 3,326
Likes: 0
From: Taylor TX
NCM Sinkhole Donor
I just had 1 fouled fuel injector cause misfire, which created "sympathy misfire" on other cylinders.
During acceleration or cruising, it felt like half the cylinders just shut down. Dramatic reduction in power. Exhaust note changed significantly too.
During acceleration or cruising, it felt like half the cylinders just shut down. Dramatic reduction in power. Exhaust note changed significantly too.
Thread Starter
Racer
Joined: Jul 2002
Posts: 303
Likes: 0
From: Sugar Land TX
I'm getting intermittant engine vibration in the 3000-4000 rpm range under high load and heavy throttle and there's some backfiring. This started happening right after my tranny was rebuilt with HD parts and torque converter cut opened and cleaned. It kinda feels like timing is being pulled or traction control is kicking in. The shop that did the job is saying that it's caused by misfires. I'm trying to differentiate it from misfire or perhaps the converter being out of balance, loose bolts, etc. I didn't have this problem before the tranny rebuild.
While at idle, there is an occasional stumble and it just goes into a series of mad crack shakes. My scanner is showing no misfire under load. I've got misfire detection disabled on low RPMs (<1000 rpm) due to a cam.
I pulled the plugs and wires and everything looks okay. One of the plugs has a bent tip but I don't think that would affect anything? I'm going to replace the plugs and go back to stock wires and see if that helps.
While at idle, there is an occasional stumble and it just goes into a series of mad crack shakes. My scanner is showing no misfire under load. I've got misfire detection disabled on low RPMs (<1000 rpm) due to a cam.
I pulled the plugs and wires and everything looks okay. One of the plugs has a bent tip but I don't think that would affect anything? I'm going to replace the plugs and go back to stock wires and see if that helps.
Drifting
Joined: Apr 2002
Posts: 1,614
Likes: 1
From: DFW TX
It's tougher to spot at idle with a lumpy cam, but one check is also pulling the injector connectors at idle, if one causes no change, that is your problem cylinder. On mine the idle seemed fine, but I had also been tweaking the idle VE to get it to idle well, not knowing the chang was probably the bad wire.
The backfiring is a sure sign of it on my car, it is often the unburnt fuel from the non-firing cylinder igniting in the exhaust system. On mine the plug showed to be wet and darker than the rest. (I was getting fuel, but no spark) It could also be a failing injector, if the plugs are clean. Hope the plug/wire change catches it for you.
The backfiring is a sure sign of it on my car, it is often the unburnt fuel from the non-firing cylinder igniting in the exhaust system. On mine the plug showed to be wet and darker than the rest. (I was getting fuel, but no spark) It could also be a failing injector, if the plugs are clean. Hope the plug/wire change catches it for you.
