Intermittent Missfire
Thread Starter
|
New User
Joined: Apr 2013
Posts: 5
Likes: 0
Intermittent Missfire
Howdy all...
Gonna try and make this short as possible, so here we go:
I have a 99 F150 Lariat 4x4 with a 5.4, 150,000 mile on it. About 2 weeks ago I blew spark plug out on #2, and a friend who said he has heli-coiled a bunch of these tried to do mine and ruined the head. Anyway, I called a local engine shop and got another PI head, only I used my cam in it. Torqued it as per the book, etc... Mind you that the engine ran perfect before all this.
Got it back together with all new plugs, new exhaust manifold, and 2 new COP's. When I start it-it runs rough for about a min, then straightens back out to run perfect again, and after a few seconds you can hear a solenoid click, then it goes back to missing again. This goes on and on... I went through all the vacuum lines and checked them, checked the egr valve, put on a new IAC, new PVC, cleaned the MAF, and checked everything else with a DVM.
I took it out and drove it.... Runs good for a minute, then it goes back to missing, then back to smooth again. This just keeps going on and on. I noticed when I hear that click, it sounds like a mad rush of air being sucked in, but I cannot locate it. I ordered a new set of COP's to try next, but I really need help on this one. I can understand if it just plain missed all the time, but this it intermittent. Also, the only code I can get is a too lean on bank 1, so I replaced the 90's and the pvc valve. Now no codes but still in and out of missing. Please help cause I am getting really PO'd at this engine right now. I don't want to keep throwing money at this, and like I said, it ran perfect before the new head.
Thanks....
Gonna try and make this short as possible, so here we go:
I have a 99 F150 Lariat 4x4 with a 5.4, 150,000 mile on it. About 2 weeks ago I blew spark plug out on #2, and a friend who said he has heli-coiled a bunch of these tried to do mine and ruined the head. Anyway, I called a local engine shop and got another PI head, only I used my cam in it. Torqued it as per the book, etc... Mind you that the engine ran perfect before all this.
Got it back together with all new plugs, new exhaust manifold, and 2 new COP's. When I start it-it runs rough for about a min, then straightens back out to run perfect again, and after a few seconds you can hear a solenoid click, then it goes back to missing again. This goes on and on... I went through all the vacuum lines and checked them, checked the egr valve, put on a new IAC, new PVC, cleaned the MAF, and checked everything else with a DVM.
I took it out and drove it.... Runs good for a minute, then it goes back to missing, then back to smooth again. This just keeps going on and on. I noticed when I hear that click, it sounds like a mad rush of air being sucked in, but I cannot locate it. I ordered a new set of COP's to try next, but I really need help on this one. I can understand if it just plain missed all the time, but this it intermittent. Also, the only code I can get is a too lean on bank 1, so I replaced the 90's and the pvc valve. Now no codes but still in and out of missing. Please help cause I am getting really PO'd at this engine right now. I don't want to keep throwing money at this, and like I said, it ran perfect before the new head.
Thanks....
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
Your at a point now that deeper diagnostics have to be done.
Get A Scanner to look at the live data while the motor is running, for clues to what is changing and for codes set.
About the only item that would cause rough running on a 'controlled basis' is the EGR opening.
Remove the hose so it can't get vacuum.
If it stops it, the vacuum regulator is leaking or being operated.
Good luck.
Get A Scanner to look at the live data while the motor is running, for clues to what is changing and for codes set.
About the only item that would cause rough running on a 'controlled basis' is the EGR opening.
Remove the hose so it can't get vacuum.
If it stops it, the vacuum regulator is leaking or being operated.
Good luck.
More Turbo
Joined: Aug 2011
Posts: 544
Likes: 2
Howdy all...
Gonna try and make this short as possible, so here we go:
I have a 99 F150 Lariat 4x4 with a 5.4, 150,000 mile on it. About 2 weeks ago I blew spark plug out on #2, and a friend who said he has heli-coiled a bunch of these tried to do mine and ruined the head. Anyway, I called a local engine shop and got another PI head, only I used my cam in it. Torqued it as per the book, etc... Mind you that the engine ran perfect before all this.
Got it back together with all new plugs, new exhaust manifold, and 2 new COP's. When I start it-it runs rough for about a min, then straightens back out to run perfect again, and after a few seconds you can hear a solenoid click, then it goes back to missing again. This goes on and on... I went through all the vacuum lines and checked them, checked the egr valve, put on a new IAC, new PVC, cleaned the MAF, and checked everything else with a DVM.
I took it out and drove it.... Runs good for a minute, then it goes back to missing, then back to smooth again. This just keeps going on and on. I noticed when I hear that click, it sounds like a mad rush of air being sucked in, but I cannot locate it. I ordered a new set of COP's to try next, but I really need help on this one. I can understand if it just plain missed all the time, but this it intermittent. Also, the only code I can get is a too lean on bank 1, so I replaced the 90's and the pvc valve. Now no codes but still in and out of missing. Please help cause I am getting really PO'd at this engine right now. I don't want to keep throwing money at this, and like I said, it ran perfect before the new head.
Thanks....
Gonna try and make this short as possible, so here we go:
I have a 99 F150 Lariat 4x4 with a 5.4, 150,000 mile on it. About 2 weeks ago I blew spark plug out on #2, and a friend who said he has heli-coiled a bunch of these tried to do mine and ruined the head. Anyway, I called a local engine shop and got another PI head, only I used my cam in it. Torqued it as per the book, etc... Mind you that the engine ran perfect before all this.
Got it back together with all new plugs, new exhaust manifold, and 2 new COP's. When I start it-it runs rough for about a min, then straightens back out to run perfect again, and after a few seconds you can hear a solenoid click, then it goes back to missing again. This goes on and on... I went through all the vacuum lines and checked them, checked the egr valve, put on a new IAC, new PVC, cleaned the MAF, and checked everything else with a DVM.
I took it out and drove it.... Runs good for a minute, then it goes back to missing, then back to smooth again. This just keeps going on and on. I noticed when I hear that click, it sounds like a mad rush of air being sucked in, but I cannot locate it. I ordered a new set of COP's to try next, but I really need help on this one. I can understand if it just plain missed all the time, but this it intermittent. Also, the only code I can get is a too lean on bank 1, so I replaced the 90's and the pvc valve. Now no codes but still in and out of missing. Please help cause I am getting really PO'd at this engine right now. I don't want to keep throwing money at this, and like I said, it ran perfect before the new head.
Thanks....
Was this truck used while the plug was out?
I know, but it has been done and
it ruins the cats really fast.
Keep us posted
Thread
Thread Starter
Forum
Replies
Last Post
The_Mad_Scientist
1997 - 2003 F150
3
Apr 2, 2019 10:21 PM
bduke23
Explorer, Sport Trac, Mountaineer & Aviator
12
Aug 8, 2018 11:05 PM
