Hi this is my 1st post on here and hope its not in the wrong area etc..
I bought my son a 1998 SC stx 4.6 for his 15th birthday to have a father son project for a year until he turns 16. well everything has been going smooth with the project (replacing simple stuff like brakes, suspension, battery, tune up , a 3 inch lift, etc) when i noticed the truck went from running as smooth as you could ask a 1 owner 113k truck to run to jumping and skipping and jerking all of a sudden. 1st time started truck fine ran about 5 mins or 3 miles then the whole jerk jump bang thing occurred, cut truck off and wouldnt start ....let truck sit for 2hrs and started right up. 2nd, 3rd and 4th trips were the same. so i assumed the fuel filter was claugged thinking after it sits the fuel eventually bleeds thru to start, well it went on like a breeze and actually seemed to take away a little of the jerk jump bang. So like any good Father i ran down and got all 8 bosch iridium spark plugs and spark plug wires. spent the afternoon tackling this job with my son, oddly enough i started on the driver side and it went as expected, learned some new curse words and eventually got it done. the plugs looked fouled and typical. THE REAL PROBLEM is when we moved to the passenger side, pulled what i believe is 1-2-3-4 and every single one was dripping wet / rusty colord boots and of course im thinking worse case but dont want to discourage him so im just working away. i blew wells out really good before plug removal and seated plugs with anitiseeze and dilecs grease, insured all boots were seated completely down and double checked it 2 more time ran truck about 5 miles and still jerk jump bang???? and why would water be in all four spark wells??? oil is clean and no signs of water and coolant is exactly where it is suppose to be aside from being a lil rusty / needs to be flushed and will. im sorry if post was too long again this is my 1st post and constructive criticism is welcomed. any advise or recommendations would be greatly appreciated

 

You need to take those Bosch plugs OUT - they have a history of disintegrating in the Triton engine.

Replace them with OEM Motorcraft, do NOT use antiseize, and torque them to 28 ft/lb.

Replace the plug wires with Motorcraft (aftermarkets don't work well unless they are racing wires), use dielectric grease. Inspect the coil packs carefully for cracks and carbon tracking.

 

There are two hoses that go to your heater core above the passenger side cylinder head, those are prone to leak, and if they are bad enough they will fill your spark plug holes full of antifreeze and it takes forever to dry them out, need to spray every spark plug hole out , make sure they are dry as possible, put some motorcraft plugs in, and lay an old t shirt under those two hoses and have someone rev up the truck when it's warm and they will usually show alot of leakage

 

thanks for the input. will do tonight

 

Ok i have change spark plugs to motor craft fine tip (they said it was the same as when it rolled out of the factory) put lots of dielectric grease on them and seated all plugs to 28ftlb and still skipping? i inspected both coil packs and appear not cracked and inside each coil where the wire goes in they look shiny new? i also ran a can of gas treatment sea foam in to help clean injectors. i ran truck for an hour watching for water from heater coil and couldnt see any (going to chalk up water in plugs to son washing truck for now) do you think it could be anything other than the coil packs ? thanks for your help

 

Have you pin-pointed which cylinder is misfiring?

Have you scanned for DTC's (Codes)?

 

What brand plug wires did you use?

You definitely are going to get water in the wells if you wash the engine - and that can cause all kinds of electrical glitches too. You may want to pull all the injector connectors and check for moisture and corrosion.

 

Does that motor have 2 coils or cops? If it is 2 coils I believe you can switch them, then see if the issue follows the suspected coil.

 

2 coils, but without a code to indicate which cylinder or cylinders are misfiring, that probably won't help.

 

Yea, H20 can be very bad for these engines. You can wash them, but you have to real careful not to screw yourself doing so.

If you own an air compressor, blow what you can at the connectors. Most of your connectors are weather tight, - but water can find a way when forced upon them.

Right definitely blow out the spark chambers (plug wells) as glc mentioned. They hold water unfortunately. Dry the ignition components best you can. You CAN short out a lot stuff, - even new stuff after replaced so....

 

Gotcha, I thought he knew which one (s) weren't firing. Yup need a code.

 

Did you replace the plug wires?

 

^^^

I've asked what brand and he hasn't told us yet.

 

Sorry guys, i have been out of town for several days without my computer. and my iphone messaging just sent me all these messages at 1030 monday. They are autolite professional grade wires. the passenger side was holding water not the driver. He did not wash engine just truck, this is what boggles me. yes it has 2 coil packs and i will replace this wknd. also code read was #3 misfire before replacement of anything. once everything was done its still skips a bit but no code light yet, may run it this wknd to see if light will pop up. (oh another thing once you drive truck for about 30min and shut it off it will not crank back up for atleast 30min to an hour. thats why i thought maybe fuel filter was claugged. i really do appreciate all the input and im sorry for the delay. havent been on vacation in about 2yrs and finally had a chance last week so left the laptop.

 

Was it antifreeze in the holes? the heater core lines run above cylinders 3&4 if they leak you'll get antifreeze in those holes. There gonna tell you that Motorcraft wires are the only way to go...