Can't pass inpsection because of misfire code please help
09-29-2012, 03:49 PM
#1
Senior Member
Thread Starter
iTrader: (1)
Join Date: 09-09-10
Location: New Hampshire
Posts: 584
Likes: 0
Received 0 Likes
on
0 Posts
Can't pass inpsection because of misfire code please help
Like the title says I need to get inspected this month and my car keeps throwing a random misfire code p0300. The code started happening about 3 days after I got tuned for 60's a 2.8 and 7 gph50/50 water meth. I've checked & replaced plugs (BKR7E's gapped at .034), vacuum leaks, reinstalled the injectors as well as cleaned the insulators, replaced the front oxygen sensor and had my tuner go through the tune twice. The misfire only happens at idle and while decelerating never at WOT or while cruising and runs fine. I've read up and checked everything, I was told by my tuner that it might be a crank sensor but I want to check everything before I go and put a part in it. I'm at a total loss if anyone else has any ideas or has dealt with this please help.
09-29-2012, 03:51 PM
#2
Senior Member
Join Date: 09-29-06
Location: california
Posts: 3,120
Likes: 0
Received 0 Likes
on
0 Posts
Cleaned and made sure of MAF/Throttle body proper operation? Worst case if you cant find it and have to pass inspection have your tuner disable the code, take it in pass inspection then throw parts at it!
10-01-2012, 08:24 AM
#6
Senior Member
I think I've read alot of posts over the years that it was infact the 60 injectors that cause that problem.
Plugs are probably fouling at Idle,did you change the plug to the recommended types for the parts you put in.
Plugs are probably fouling at Idle,did you change the plug to the recommended types for the parts you put in.
10-01-2012, 09:05 AM
#7
Senior Member
Thread Starter
iTrader: (1)
Join Date: 09-09-10
Location: New Hampshire
Posts: 584
Likes: 0
Received 0 Likes
on
0 Posts
Ive been reading the same thing about 60s, my tuner has done everything he can. I put cooler plugs in etc. Im going to try some autolites and see what happens.
10-09-2012, 09:14 AM
#8
Senior Member
Thread Starter
iTrader: (1)
Join Date: 09-09-10
Location: New Hampshire
Posts: 584
Likes: 0
Received 0 Likes
on
0 Posts
Bump. Replaced injector insulators and gapped plugs at .038 barely any misfires at idle now still throwing p0300. Still misfiring at decel. Any other ideas? Ready to de-mod and dump this piece of ****.
10-09-2012, 10:23 AM
#12
ive got a p300 too and i also replaced my plugs thinking it was because i was fouling them out with my 60's. nd yea the code still comes up. i've replaced my camshaft position sensor, cleaned my TB and MAF, idk what else it could be but i need my tune tweaked so we'll see where that goes. its the same thing in IL and i gotta pass emissions in feburary
10-09-2012, 10:43 AM
#13
60# injectors throw p0300 quite often, i've had it off and on for 3 years now. It is hard for any tuner to get them to idle correctly.
I have run into the same issue here in TX with inspection, what I learned is that my car does not throw the code when the AC is on due to the increased load on the engine at idle. You can clear the code, drive around with the AC on for a bit, and take it in for inspection. Or you can have your tuner delete that code permanently, set your idle a bit higher, and see if you can pass then.
I have run into the same issue here in TX with inspection, what I learned is that my car does not throw the code when the AC is on due to the increased load on the engine at idle. You can clear the code, drive around with the AC on for a bit, and take it in for inspection. Or you can have your tuner delete that code permanently, set your idle a bit higher, and see if you can pass then.
10-09-2012, 10:51 AM
#14
Senior Member
Thread Starter
iTrader: (1)
Join Date: 09-09-10
Location: New Hampshire
Posts: 584
Likes: 0
Received 0 Likes
on
0 Posts
I put a .038 gap on the bkr7e's and it smoothed out at idle to almost nothing and cruising but it's just on decel I get misfires. Inspection was last month and I failed so I'm under the gun, losing sleep over it.
10-09-2012, 11:00 AM
#17
2.8 and 60s, started throwing p0300
its that mild cam mod ^_^
the weirdest thing, i installed the zzp intake and havent had the code since then, i even have an exhaust leak...like always
i figured the additional air from the leak was trigging the code at first as it would pop up everything the leak would return
been on the 60s since 2010 and put the intake on back in June/July of this yr
had an AEM shorty pipe intake before
its that mild cam mod ^_^
the weirdest thing, i installed the zzp intake and havent had the code since then, i even have an exhaust leak...like always
i figured the additional air from the leak was trigging the code at first as it would pop up everything the leak would return
been on the 60s since 2010 and put the intake on back in June/July of this yr
had an AEM shorty pipe intake before
10-09-2012, 11:00 AM
#18
Senior Member
Thread Starter
iTrader: (1)
Join Date: 09-09-10
Location: New Hampshire
Posts: 584
Likes: 0
Received 0 Likes
on
0 Posts
60# injectors throw p0300 quite often, i've had it off and on for 3 years now. It is hard for any tuner to get them to idle correctly.
I have run into the same issue here in TX with inspection, what I learned is that my car does not throw the code when the AC is on due to the increased load on the engine at idle. You can clear the code, drive around with the AC on for a bit, and take it in for inspection. Or you can have your tuner delete that code permanently, set your idle a bit higher, and see if you can pass then.
I have run into the same issue here in TX with inspection, what I learned is that my car does not throw the code when the AC is on due to the increased load on the engine at idle. You can clear the code, drive around with the AC on for a bit, and take it in for inspection. Or you can have your tuner delete that code permanently, set your idle a bit higher, and see if you can pass then.
10-09-2012, 11:24 AM
#21
Senior Member
Thread Starter
iTrader: (1)
Join Date: 09-09-10
Location: New Hampshire
Posts: 584
Likes: 0
Received 0 Likes
on
0 Posts
Yeah it's on my interceptor. Pretty much and time I'm in gear and let off sometimes its immediate misfire or it takes a few seconds not always predictable. I'll try messing with gaps again.
