I installed 6 of 8 plugs and the engine was running smooth. In between changing the plugs, I have done other routine maintenance such as flushing the cooling system, replacing all the brakes and master cylinder. I buttoned everything up this morning and she was running fine on my way to and back from Americas Tires.

Later, I took it for a test drive to the hazardous waste center to dump all my oil and coolant. I noticed it was running rougher than normal. This concerned me. I checked all the coil pack and fuel rail connections as most were removed. On one of the coil packs that I did not remove, I noticed that the 7 mm bolt was not tight and I tightened this. I put everything back together and it's still running rough.

I flushed the cooling system with ThermoCure rust remover and cooling flush. When I opened the degass bottle, it smelled sort of like gasoline as it still had the chemical flush in it. I checked the oil dipstick for foam or anything indicating a blown head gasket. It looked like a fresh oil change. I do notice a white smoke at startup that I see on many vehicles while they are warming up.

The engine did not throw any codes.

My conclusion not knowing much about the 5.4 2v engine is a bad plug, coil pack, or blown head gasket.

I made an appointment with a local mechanic for diagnostics.

 

Try to change the other two plugs and coils. If it was a head gasket there would be other signs

 

Thanks. I plan on replacing the other 2 plugs and coils on Monday. I bought a special low profile 7mm ratcheting wrench, magnetic 7mm socket, and a 1/4" passthrough socket set. I ordered 8 COP bolts in case I lose 1 or 2.

 

Double check the wiring harness connectors for the COP's----there are locking tabs on them that if not fully engage with an audible click or that locking tab has been broken during removal they can cause intermittent connection and the rough idle.

Typically the PCM will throw a code but on your year it might take a while before that happens. A code scanner may show a bad connection as a pending DTC for the offending COP and won't throw a SES or CEL lamp immediately.

Also double check any vacuum connections that may have been jostled loose during the plug refreshing,

If you removed and/or unplugged the MAF sensor has that been reconnected? Are all the intake duct clamps tightened?

 

I will check all the obvious today. I keep looking at my spare 1998 V6. It's never so much as given me any trouble in 7 years other than 1 flat tire.

The misfire/rough idle happened after removing the master cylinder. There is an electrical connection to the master cylinder. The vacuum to the booster is good. I may switch some air ducting from the V6 van if they are the same.

I don't think the 1998 E350 5.4 throws the codes immediately.

I am having buyers remorse. While I was in no hurry to get a van, this one popped up and it was running really good. Down the road, I want to get a 2004 or newer van with disk brakes all around and traction control.

 

I drove the van to REI today to pick up some camping chairs and the van finally threw 2 codes. Never seen a guy so happy to have the engine check light come and throw some codes!

P301 and P302.

Looks like I will be busy on Memorial Day.

 

Those DTC's show cylinder's 1 & 2 are acting up----remove and reinstall them, maybe pull the plugs out for an inspection since you're already there.

If you're up for the extra work swap a COP from another cylinder, to see if the miss follows the COP. If it does then that points to the COP being faulty. That's not usual but its been known to happen.

And yes those DTC's and even the SES lights can be helpful at times---usually we're cursing their appearance.

 

I replaced #1 cop and drove the van 100 miles and it threw the P0302 code again at mile 100 just as I was exiting to REI again to buy more camping equipment. Maybe I should stop going to REI!

I also noticed that the coolant is foamy yellow and still smells like gasoline after flushing for nearly 30 minutes with thermostat removed.

I flushed the cooling system with ThermoCure rust remover after replacing a failed radiator. After flushing and driving the vehicle I noticed rust colored foam build up in the degas bottle. After letting the engine cool, I opened the degas bottle and it smelled like gasoline. I bought the Block Chek brand combustion leak test kit and it went from dark blue to yellow indicating that I have a combustion leak.

The P0302 misfire may be caused from the combustion leak.

I think I have either a cracked block or failed head gasket!

What are my option? Head gasket job? Rebuilt engine? Punt and kick this van down the road?

 

Yeah that REI is the offending entity here!

Pull the plugs from #1 & #2 to check them---if you have a borescope use it to look inside the cylinders. Any signs of coolant in either cylinder does suggest a head gasket issue.

I'd do a leak down check of the offending cylinder before assuming its the worst case scenario. Talk with your trusted mechanic (the rear end guy?) and get his input first---don't wanna tear into replacing head gaskets without a sound diagnosis. The intake manifolds on the 5.4's in general have been known to be at the root of such things but do let your mechanic look at it first.

Also you might make visiting the Modular Motors V8 sub-forum a regular read----since these engines are used in the F-Series too there's a good base of experience there. Keep in mind your motor is the 2 valve version---that is asked if not provided in any posts you add or new threads started.

HTH

 

I posted on the modular motors sub forum. I took the van out yesterday on it's maiden test run. It handled the mountain grades as good as the diesel with the exception of only having 4 gears in the transmission rather than 5. It has almost as much power. It's so much quieter! My oldest finally admitted that he does not like the noise of the diesel.

I am drinking my morning cup of coffee and enjoying the quiet house. Time to pull the COP again. I have a boroscope and I cannot remember where I stashed it. My life is a little out balance working on 3 different white vans.