I went and washed the motor of my 99 expedition off two days ago. It started misfiring. Read the code and it was the coil pack on number 4 cylinder. replaced that one then got a different code for the coil pack on a different cylinder. Replaced that one too. Now I have no codes but it is still misfiring. It idles fine but as soon as you put it into gear it starts missing. When in park there is a hesitation as you rev it up between 1500 and 2000 rpm's.
Help with engine misfire
- Thread starter branchrs
- Start date
Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.
Captain Morgan
Full Access Members
How much time has the engine actually ran since you washed it?
Are you convinced that all of the parts have really dried out?
I would let it sit and idle for an hour or so with the hood down.
Once you get this under wraps, buy some silicone and seal the connections to the COPs etc, as outlined in another thread here, search for key words to find.
.
Are you convinced that all of the parts have really dried out?
I would let it sit and idle for an hour or so with the hood down.
Once you get this under wraps, buy some silicone and seal the connections to the COPs etc, as outlined in another thread here, search for key words to find.
.
Did you check the spark plugs or make sure the plug wells were dry?? Most likely its not the cops themself but water in the plug well causing it to misfire to ground.
The cop boot does not seal as it should on many older expys. I use dielectric grease (non-conductive) on the boot where it seals to the plug well.
Last edited:
Misfire is generally related to the ignition. I personally would change all the spark plugs at this point. Check the coils for any obvious cracks when you have them off. Also check the spring in the boot for any signs of corrosion.
Last edited:
Captain Morgan
Full Access Members
Yup. Being a 99 if you don't know when the plugs were changed last, new plugs and COPs are in order.
.
.
it does have a 188000 and this is the lonely problem it has had. and i usely work on all my cars myself becuase when you have four cars on the road two being teen cars you cant afford to take them to a dealer and at the end of the month it has to go to flordia
splintrcel
Full Access Members
I dumped coolant on my engine like an idiot and had the same issues ur having. I just replaced the plugs and cleaned everything out good and dry and replaced the plugs but not the coil packs.
QbanCgar
Full Access Members
yeah my Expy ('99) is misfiring slightly. i noticed mainly when i was on an off ramp & coasting, & when i finally gave it gas it didn't seen i was getting the acceleration i needed as well as the misfiring. i also noticed it coming off an off ramp, give it some gas & you can feel the misfire. i'm having new plugs put in today so i'm hoping this is the cure.
Similar threads
