P0300 missfire after headers
10-20-2013, 10:57 PM
#1
On The Tree
Thread Starter
Join Date: Oct 2012
Location: Nashville, IL
Posts: 158
Likes: 0
Received 0 Likes
on
0 Posts
P0300 missfire after headers Alright so the V has been down for the past twoish months. Water pump started leaking, starter was going out. I had new motor mounts to put in along with an Ati damper. So I took care of all that and decided to install pacesetter headers as well. After I've install everything I am now getting a p0300 code. Engine misses at idle occasionally, sometimes under part throttle and misses hard under heavy acceleration. Car has no power at all really it feels like. The plugs are only about 5k miles old. Plug wires never replaced as far as I know and it has 102k miles. I didn't have any problems getting the wires off. I visually inspected them and look fine, but that doesn't mean a whole lot. I'm not really sure where to start. Should I start with the plugs and wires? Should I pull the valve covers and check for broken valve springs? If it was a bad o2 they would throw an o2 specific code right? I didn't use o2 extensions, the passenger side wire almost seemed to be a stretch for the o2. Any help would be greatly appreciated.
10-20-2013, 11:26 PM
#2
Stock plug wires are known to come apart when you pull them if your not careful. Id lean towards that being the issue. Its also possible the you cracked the porcelain on one of the plugs when installing and sometimes you can barely see it. Cheap insurance is to throw some Tr55's in it and some plug wires.
10-21-2013, 01:44 PM
#5
On The Tree
Thread Starter
Join Date: Oct 2012
Location: Nashville, IL
Posts: 158
Likes: 0
Received 0 Likes
on
0 Posts
I've checked them all and pushed as hard as I can and reseated them a couple times, but I went ahead and ordered new plugs and wires. I'll give that a try. HPTuners eventually popped up with Cylinder 8 misfire. I switched that wire with another cylinder but it hasn't thrown a specific cylinder code yet.
10-22-2013, 10:29 PM
#6
On The Tree
Thread Starter
Join Date: Oct 2012
Location: Nashville, IL
Posts: 158
Likes: 0
Received 0 Likes
on
0 Posts
Got a new plug and tried just cylinder 8, misfire went away and no more codes. Plug looked fine though. I'm going to finish installing plugs and wires. Car feels still slower than before it seems though. Maybe I'm just used to driving the turbo 4 cylinder around the past couple months, but it's only around 260-280whp.. sounds like I need more mods!
