Random Missfire Question!
Nov 23, 2009, 06:33 PM
#16
Evolving Member
I have this problem too, but it only acts up about once every two months.
The CEL comes on and the whole car bogs, i lift off and it's gone.
The random mis is so random. i have even changed plugs and wire. ohmed all of them out too.
I usually just clear the check engine light and drive for another two months.LOL
The CEL comes on and the whole car bogs, i lift off and it's gone.
The random mis is so random. i have even changed plugs and wire. ohmed all of them out too.
I usually just clear the check engine light and drive for another two months.LOL
Check fuel and make sure that within specifications to both.
Nov 29, 2009, 02:11 PM
#18
Newbie
I have had this problem recently. The issue was being caused by over-boosting. Due to the change in weather (colder, denser air), my car was boosting well past 26 psi (tuned for 22-23 psi). I was receiving the MIL indicator (Random Misfire code) and the car would not run past 70mph without making a fluttering noises and sputtering. Needless to say, once the boost was backed down, my issue went away. (Thanks Atlantic Motorsports)
Dec 13, 2009, 09:14 PM
#19
Newbie
Join Date: Apr 2008
Location: Colorado
Posts: 50
Likes: 0
Received 0 Likes
on
0 Posts
Hey EvoM, well ive been reading through these threads about the P0300 codes and Im still trying to track down the problem on my friends 05 MR.
So here's whats up, its an 05 MR as i stated above, Rom ID is 96940011. We live in a cold state, and recently here in Colorado we've been seeing some well below 20 degree temperatures, and about 2 weeks ago he was sitting at a light at Idle and his SES came on, checked it with EvoScan and it pulled a P0304, Cylinder 4 misfire.
Now note that the boost on this car has been raised to about 22-24 and it has a tuned timing and AFR Map.
the car has never had these problems before on the same tune until recently. The plugs are 60k plugs with 30k on them, just checked today and they look to be fine.
So, when we were just usually driving around cruising, I figured i'd log some data and see whats up. I figured if it was misfiring we would detect knock because one of the cylinders would be out of time.
Oh,and need I note that a week after the initial code a P0300 code came up for multiple misfires.
So, we were driving and It had like a hierarchy of knock from 5 counts tapering down when we went 3rd gear WOT. and random what seems like phantom knock when just normally cruising.
we didnt hit this code for a good hour of driving until all of a sudden right around idle the SES got tripped and it pulled P0304.
the car is sitting at 6* advance at idle right now. which doesnt seem like a lot to me based upon stock is 5*.
We dont think its the plugs because we've checked those, its a 6spd and the transmissions feels solid and just I really doubt a mainshaft is the issue like the TSB's say. Its wasted spark ignition so Id think it would have misfires on the two cylinders which get spark from the same coil if it were the coil
So I'm left with it being 1) the cold temperatures, 2) plug wires, 3) some how the plugs, 4) tune is off..yet...I doubt that.It's never had that problem before. and 5) possibly just an old ROM version and its freakin out.
Note the car has basic bolt ons, Megan racing exhaust mani, perrin TBE, Intake, Injen IC piping, basic stuff. No cams, no crazy injectors. Car has 72k on the ODO.
just lookin for more idea's and or what to check first.
Thanks EvoM
So here's whats up, its an 05 MR as i stated above, Rom ID is 96940011. We live in a cold state, and recently here in Colorado we've been seeing some well below 20 degree temperatures, and about 2 weeks ago he was sitting at a light at Idle and his SES came on, checked it with EvoScan and it pulled a P0304, Cylinder 4 misfire.
Now note that the boost on this car has been raised to about 22-24 and it has a tuned timing and AFR Map.
the car has never had these problems before on the same tune until recently. The plugs are 60k plugs with 30k on them, just checked today and they look to be fine.
So, when we were just usually driving around cruising, I figured i'd log some data and see whats up. I figured if it was misfiring we would detect knock because one of the cylinders would be out of time.
Oh,and need I note that a week after the initial code a P0300 code came up for multiple misfires.
So, we were driving and It had like a hierarchy of knock from 5 counts tapering down when we went 3rd gear WOT. and random what seems like phantom knock when just normally cruising.
we didnt hit this code for a good hour of driving until all of a sudden right around idle the SES got tripped and it pulled P0304.
the car is sitting at 6* advance at idle right now. which doesnt seem like a lot to me based upon stock is 5*.
We dont think its the plugs because we've checked those, its a 6spd and the transmissions feels solid and just I really doubt a mainshaft is the issue like the TSB's say. Its wasted spark ignition so Id think it would have misfires on the two cylinders which get spark from the same coil if it were the coil
So I'm left with it being 1) the cold temperatures, 2) plug wires, 3) some how the plugs, 4) tune is off..yet...I doubt that.It's never had that problem before. and 5) possibly just an old ROM version and its freakin out.
Note the car has basic bolt ons, Megan racing exhaust mani, perrin TBE, Intake, Injen IC piping, basic stuff. No cams, no crazy injectors. Car has 72k on the ODO.
just lookin for more idea's and or what to check first.
Thanks EvoM
Thread
Thread Starter
Forum
Replies
Last Post
