I have a 02 expy with a triton 5.4L i am the 3rd owner it has been a good truck in december of 08 it got a new AAMCO tranny and i have 112,000 on the odometer. Recently the engine started running rough under a load NO C E L though. awhile back i had the #8 COP go **** up and it threw a CEL and i replaced it and bought an extra one just incase.. Anyways i have been pulling my hair out here trying to find the misfire I am planning on swapping COP's 1 by 1 to see if another is going bad, but i read on here that another guy had almost the same issue and it was a bad MAF. i really need some good advice and pointers from you guys who have expierenced this issue before. i am a disabled father of 6 kids and this is the family truck. i need help from my fellow blue bloods brothers!

thank you,
Clay

 

I am assuming you've already eliminated the spark plugs because they're relatively new, right? You did mention replacing the COP but nothing to indicate that the plugs were replaced.

Are there any modifications on the vehicle, such as a K&N style filer or a CAI? These can ultimately damage the MAF sensor by contaminating the sensor wire with oil. If not, it's still possible that the MAF sensor is not working properly but it's not very cheap to replace simply on a hunch.

If you could provide a little more history on the maintenance, it would be helpful.

Thanks.

 

Thank you for your reply, as to any mods on the truck ,No it is bone stock . i can provide a list of things i have done.I replaced #8 COP and Fuel injector ( it was leaking gas). I replaced all 8 plugs and boots in march. I used motorcraft single platinum and gapped them to factory specs. I also replaced the +battrey cable and terminals. i have changed the oil and oil filter every 2,500 miles.. that is all i have done to the truck.
It started doing it under load only at first then progressively got worse. it slightly misses at idle in park. but when you engage it into drive and step on the gas it it does it really bad at around 1,500 to 1,900 rpm's and it only does it when it has warmed up. On a cold engine it seems fine.

My Wife and I take the best care of our vehicles possible and we own all ford cars and trucks, we have the 02 expedition an 03 sport trac and my mother in law has a 98 v6 mustang convert. i useed to own a 81 f-250 with a mean 400M 4x4 and a c-6 with a stage 2 shift kit 9" 3rd member. converted from ifs to straight axle.

anyways i hope the info i provided can shed some light. thank you for all your help i really appreciate it.

Clay

 

Bump ???? Please

 

EGR valve sooted up?