'99 Random Misfire
#1
#2
#4
Well, I fully agree that the PCV elbow can cause a "random misfire" P300 code. I just bought a 99 SD SC 4x4 V10 and it ran like a bag O crap. Decided to throw a set of plugs and known good coils in it and noticed a crack in that PCV hose.
When I removed it , it had two 1" long cracks in it.. Being sunday and all... I carefully cleaned and taped the hose.Monday I will get a new one from the dealer.
Now the truck runs like a million bucks!!!
BTW I just bought this truck for $2500 and everything works.. ESOF 4x4 and all.
When I removed it , it had two 1" long cracks in it.. Being sunday and all... I carefully cleaned and taped the hose.Monday I will get a new one from the dealer.
Now the truck runs like a million bucks!!!
BTW I just bought this truck for $2500 and everything works.. ESOF 4x4 and all.
#5
Well, I fully agree that the PCV elbow can cause a "random misfire" P300 code. I just bought a 99 SD SC 4x4 V10 and it ran like a bag O crap. Decided to throw a set of plugs and known good coils in it and noticed a crack in that PCV hose.
When I removed it , it had two 1" long cracks in it.. Being sunday and all... I carefully cleaned and taped the hose.Monday I will get a new one from the dealer.
Now the truck runs like a million bucks!!!
BTW I just bought this truck for $2500 and everything works.. ESOF 4x4 and all.
When I removed it , it had two 1" long cracks in it.. Being sunday and all... I carefully cleaned and taped the hose.Monday I will get a new one from the dealer.
Now the truck runs like a million bucks!!!
BTW I just bought this truck for $2500 and everything works.. ESOF 4x4 and all.
#6
#7
Trending Topics
#8
#9
P0300
I had the same issue last year. I decided to replace all the COP's, boots, and plugs. Problem solved. I got the COP's on ebay for around $100 for the set of ten. Supposedly those boots are the cheapest route to go as far as replacement/solutions go, but, i bought my rig used and had no idea what the previous owner(s) had replaced. It also had 80k on it. In some forums i've read that any kind of coolant leak or hard water spray will cause the boots to fail and the COP will somehow arc through the boot occasionally, causing the "random" misfires. Good luck
#10
OK. I am asking because i don't know where to start. Should i start with plugs? Coils? Plug boots? PCV? I'm not sure. I don't want to spend a lot of money to find out something is not the problem. I'm guessing start with something cheap like plugs? Then boots and so on...?
The rubber PCV hose was $26 at the dealer. I happened to have a set of coils sitting around since i have friends that work in the engine plant where they build the engine.
Its easier to change the plugs and boots than I thought it would be except the back 2 on the pass side.
Remember, if your not bleeding, your not working... lol
#11
Mine was running like crap and i cleaned everything i could get to externally. IE new fuel filter, cleaned IAC, MAF, EGR, IAT, and pulled all the boots and checked anddi-electric greased them. One day later the "pending P0300" changed to "P0301 missfire." Replaced cop on number 1 for 32.00 and all is great. All the cleaning took a few hours but cost only 20.00 for the maf cleaner, carb cleaner and di-electric grease. I also checked my pcv elbow first and found it to not be cracked so went on with the cleaning of all those other things. I guess I am saying start with looking at the pcv elbow. You need to remove it to look at it good. Then go on and do MAF, IAC, EGR, and then the boots. Change up the order if you want but that is where I would start. There is my two cents. Out!
#12
My dad's friend is a "Backyard mechanic". But he really knows his S**t. He said that it could have slipped out of time if it is misfiring randomly and also when it starts, it turns over very slow like a car out of time. It cranks almost like the battery is dead. Could this be the problem?
#14
#15
Thanks SDV10 for giving me the idea of checking the PCV elbow. I had multiple issues when I bought this 99 F250 with the V10. hard misfire at first. Threw codes P0174, P0340, P0302, P0300. I didn't know the condition of the plugs and saw that 5 of the COPs were aftermarket. I changed all the plugs, boots, springs and COP on #2 (with new dielectric grease). Cleared the codes and test drove. Miss was not as bad but still there between 1300 and 1800 RPM in overdrive. Threw code P0302 and P0300 so I swapped the #2 and #3 injectors. That cleared the P0302, but still had that P0300 code and it still had that miss. Stumped, I logged in here and saw your post and just like you described, I had a hole in the PCV elbow. I wrapped it with electrical tape and 'wallah' the engine runs perfect. Got the elbow on order.
Thread
Thread Starter
Forum
Replies
Last Post
hans2112
1968-Present E-Series Van/Cutaway/Chassis
11
06-05-2012 01:12 PM