Drove my '01 5.4L about 140 miles yesterday, 0 problems. It rained all day and night and has been quite a bit more moist than the last few days/weeks/months.

Started it up this morning, backed out of the driveway. Once I actually used the accelerator, I knew something was wrong. Its running incredibly rough, like a cylinder is not just misfiring, but not firing at all. Even in park at idle, it bounces.

Never had a problem with the engine. I believe plugs were done around 80-100k (its got 202k on it), though I can't imagine plugs are the issue, given the sudden onset of the issue. It happens through the entire RPM band, but is worse when I'm not on the gas as hard. (While noticable on the freeway, it wasnt near as bad as it was when I was curising at 50 mph.)

I've heard injectors are a common issue, and one or more COPs could be bad. It was also suggested that because of the age of the truck and my gas tank having less than 1/4 left, it could be a problem with the fuel pump. Any and all ideas welcome... also, if you can include prices to get said problems fixed, I'd appreciate it.

 

Coils have gotten wet. That commoly happens to these engines when is time for a tune up. I would get the set of 8 coils from e-bay search dg508 sellers global and uneek have been used by board members with fairly good results. Probably time for plugs while your at it. Might wanta order the set of coils for the v10- the 10 pack torque your plugs to 28 lbs dry no anti seize use dielectric grease to waterproof the boots..

 

Wouldn't this have happened yesterday though, when I was actually driving in the rain? It didn't start until this morning, after the truck had sat in the garage for 10 hours. Also, this isn't the first rain or snow this year (I live in Michigan...), why would it just now happen? Nothing about the truck has changed.

 

Do you have any codes yet?
99% of the time, what you are describing is a bad COP.
Just because it didn't miss yesterday, water could have got done in somewhere overnight. Now you have the miss.

Phil

 

Nope, no codes. Kind of strange to have it shake and lurch so bad it shakes my glasses off my face, but not throw a code.

I really hope you're right. Do I get all 8 changed, along with the plugs? What should I expect to pay for labor for that?

 

So assuming its a wet COP, will it dry out and stop missing? And am I safe to drive it as is?

 

The moisture might have already did its number on them.....
You might also want to invest in a new set of cop boots as well...
They might dry out and be fine for a while but the next time it gets wet out you're going to be back to the misfires...

 

Have you driven it much with it missing?
Some times it takes a wile before it will set a code.

Naturally ,it's cheaper to just fix the bad one or two.
But if you cant find out what one to change , you might have to just get a hole set and go from there.

Phil

 

Plugs are probably due with 100k on them. But, sounds like one or more of your cop's took a dump. You would be surprised how crappy it will run when it looses just one cylinder to a misfire. Check to see if your CEL light is flashing while it is misfiring at it's worse. Otherwise you can keep driving it trying to make it misfire as long as you can and the CEL will come on. But, I would just change all 8 plugs and cop's. It's most likely due. I'm not sure what shop rates are, I know they arent cheap. I think most pay around 300? for the plug change alone. You could be looking at 500-800? Just a guess. If you have any mechanical skills at all, you can be walked right through it. It's not the easiest thing to do but with good instructions can be done by just about anyone with common sense.

 

Does your CEL or SES light come on briefly at start up? If not you might check for codes anyway. There is always the possibility that your CEL or SES lightbulb is bad in addition to the plugs and/or coils.

 

After about 80 miles of driving, it finally kicked the CEL on. I'm not sure the specific code, but it was a cylinder 1 misfire. Went to autozone, got the coil, put it on in about 3 minutes and we're all good!

Thanks for your guys' help. I'm doing my best to familiarize myself with the vehicle a little better and this kind of stuff really helps!

 

Good deal.
It makes it so much easier when they finally throw a code.
Glad ya got her running right again.

Phil