SL/R230: P0300
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Joined: Sep 2012
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2011 E550 Coupe, 1992 Corvette ZR-1, 1991 368ci ZR-1, 1990 ZR-1, 1987 Callaway TT, 05 SL600, CLA45
P0300
Getting the P0300 random misfire code on my 05 TT V12, no specific cylinder and the car goes back to running fine after the code set. Coil packs were rebuild last year, this issue started this winter when I went to put the car away. Any thoughts, my code reader does pick up on specific cylinder codes
Thanks
Lgaff
Thanks
Lgaff
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 411
Likes: 23
2011 E550 Coupe, 1992 Corvette ZR-1, 1991 368ci ZR-1, 1990 ZR-1, 1987 Callaway TT, 05 SL600, CLA45
Ran it hard, not down on power at all...no codes when I ran it hard....came on at idle...strange
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Joined: Aug 2014
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From: SW Pennsylvania
SL600
There are a lot of possible causes of the PO300 misfire on the V12. I would start with the simple and most common problems. What gas do you run? From a Top Tier station? If not, run, don't walk to your local auto parts store and get some Chevron Techron and run a tank full. It's always worked for me and solved my misfire issue. I run a bottle about every other tank as I don't have a top tier station near me.
(FWIW, the guy I bought the car from changed the ignition rail and the plugs trying to solve this issue before giving up and selling it to me. A $8 bottle of Techron solved the problem and I've never had it again with over 30K miles added to the odo....)
If it's not a fuel issue it could be anything from the fuel injector to a plug to the ignition rail and everything else in the circuit. None of which are as easy to find & fix.
Keep track of which cylinder caused the misfire, it may help figure it out if/when it happens again.
(FWIW, the guy I bought the car from changed the ignition rail and the plugs trying to solve this issue before giving up and selling it to me. A $8 bottle of Techron solved the problem and I've never had it again with over 30K miles added to the odo....)
If it's not a fuel issue it could be anything from the fuel injector to a plug to the ignition rail and everything else in the circuit. None of which are as easy to find & fix.
Keep track of which cylinder caused the misfire, it may help figure it out if/when it happens again.
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 411
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2011 E550 Coupe, 1992 Corvette ZR-1, 1991 368ci ZR-1, 1990 ZR-1, 1987 Callaway TT, 05 SL600, CLA45
I think its my tune combined with the winter blend gas, I believe they start summer blend this month.....will try the additive in the short term. I generally run Shell or BP.....odd thing is I stopped using a SHELL station near my work as it was causing my C32 to shut down on full throttle.....this is not the same station I use for the SL....
Thanks for your input
Thanks for your input
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 411
Likes: 23
2011 E550 Coupe, 1992 Corvette ZR-1, 1991 368ci ZR-1, 1990 ZR-1, 1987 Callaway TT, 05 SL600, CLA45
Still getting this code....comes on at part throttle have not seen it at idle....car still runs great idles at 600-630 pulls strong no obvious vac leaks
Tried the gas additive, new gas in the take so should be beyond the winter gas issue
thoughts?
Tried the gas additive, new gas in the take so should be beyond the winter gas issue
thoughts?
Last edited by LGAFF; Apr 23, 2017 at 12:24 PM.
Thread Starter
Senior Member
Joined: Sep 2012
Posts: 411
Likes: 23
2011 E550 Coupe, 1992 Corvette ZR-1, 1991 368ci ZR-1, 1990 ZR-1, 1987 Callaway TT, 05 SL600, CLA45
Went 90 miles today, then out of the blue at light throttle got the CE light
I am not feeling a miss with the car
I am not feeling a miss with the car
