All,

Driving home last night in very high winds yet still it didn't feel like the wind alone was all that felt wrong. CEL finally came on (first time ever in nearly 9 years) and confirmed all wasn't right. 5.4L was doing fine at idle or without much load at any rpm, but push on it harder and it was bucking so you could feel it in the chassis and the seat of your pants and power was far less than typical.

Read you guys a bit after I got home for some ideas.

Based on threads here, tonight I stopped at AutoZone to get them to read my codes - Only drove to the train station today as I didn't want to do the 110 miles round trip and the other vehicles at the house were spoken for. They don't read codes here (San Jose, CA), but they do sell you the ODBII tool and promise a full refund if returned in ten days. Of course they know full well what you are doing.

It's throwing code P0301 - Cyl 1 missing. Guess that makes sense. I cleared it and drove again recreating it. No other codes. Overall that's good news. I was worried about mass flow sensor, or O2 sensors, or really just having to shotgun the problem and spend a lot of time and $$.

From what I've read I'm thinking #1 COP or plug. Plugs were done by the dealer around 80+K, it's at 121K now.

You all have brought me this far and I really appreciate it! Knowing it's just missing takes away a lot of uncertainty!!!

My next question: Is it worth the work to switch #1 & #2 COPs to narrow it down to the COP vs plug, rather than throwing parts at it?

Thanks in advance,

 

Maybe.

If you want to throw a plug and COP in #1 only, you're looking at about $55 in parts. Since most misfires are due to either the plug or the boot of the COP failing, I'd opt for throwing a plug and a boot only into the #1 spot for about $9. Be sure to use dielectric grease.

#s 1 & 2 are the easiest to work with so you definately got lucky in that regard.

Steve

 

I guess your question has to do with how much extra cash you have and how much you want to hold onto it.

I would swap the COP's right away while you still have the scanner and see if the miss follows the COP before buying anything, but I'm a skin flint with a daughter in college so every dollar counts for me right now.

Good luck,
Doc

 

Update & still an issue: With one in college and one more going next year I wanted to see if I could narrow down the trouble before throwing parts at is and my plugs were changed around 30+K ago.

I swapped COP #1 with #2 after clearing the code (P0301).

Then I drove to see if the problem followed the COP. Guess what - NO CODE! But it's still missing, I can barely fell it at light throttle and still when I open up the trottle, especially at lower rpms, the chassis shakes.

Been driving for 3 days now - still no code - still seems to be missing and running poorly.

Ideas?

 

One at a time, unplug the fuel injector connector for #1 & 2.

One will make the problem even worse, the other will make little change.

The cylinder that has the problem will be the one that doesn't get worse.

Steve.

 

I have the same prob. I switched out the #1 & #4 cop's. Finally set another code on the way to work this am. I will go to auto zone after work & find out if it is the cop or not & let u know what I find out. BTW all of his started after putting on a K&N FIPK, thought it was oil on the mass air sensor from the filter but I cleaned it 5 times.

 

Well it didn't hold a code in memory. Went ahead & changed the #1 plug, but it didn't help. Guess I'll have the dealer do a diagnotic rather than throwing parts at it.

 

Could be a bad boot. I would replace it first and be sure to use dilectric grease.

 

How can U tell if it is a bad boot? There are no cracks or anything in the rubber & the spring appears to be fine also.