4.6 mystery hiccup - transmission or ignition ?
 

This is a on a 2004 Explorer. I hope no one minds me posting it here, THe explorer folks are just not as 'hands on' as the peope in this forum.

4.6 with 150,000 miles. I have a CEL for a EGR valve (P0104) but my symptoms are not what's listed for EGR valve failure.

The truck starts easy and runs great. If i drive like a teenager all the time i'd never notice the problem. Hit the gas and it zips through the gears and pretty soon you're looking for cops.

But, if i act my age and accelerate normally there is a hiccup around 2000 RPMs it's subtle, i can't tell if it's a misfire or the transmission slipping. The 5 speed auto (5R55) has 185,000 miles on it and they don't usually last that long.

I will change the EGR valve as soon as I can but i don't find any info that connects the EGR to my particular symptoms.

Other symptom is lousy MPG

thanks

P0104 is a MAF issue, not EGR. That could very well be your issue. Are you by chance running a K&N, or other oiled air filter on your Explorer?

https://www.obd-codes.com/p0104

Oops, that was a typo. It's P0401 (i fixed it) No, i am not running anything other than OEM prescribed parts, right down to the oil filter. But i probably should check the air cleaner.

OK, P0401 is most commonly carbon buildup in the EGR ports on a 4.6. Don't buy a new EGR yet!!!

Also, if it turns out that you DON'T have carbon buildup, check the valve to see if it holds vacuum. If it does, my issue on my truck for P0401 was actually the EGR Solenoid. It was pulsing vacuum 100% of the time....

I had a very similar issue on my 02 4.6.turned out to be coil on one of the plugs....

Also, my question about the K&N was directly related to the MAF sensor, so disregard the air filter.

I wouldn't worry about your "hiccup" at 2K until you've got this EGR issue resolved, as it can cause it to run poorly.

get the EGR issue solved before you do anything else

Thanks. As i drive the car the problem gets worse and now it's starting to show up at idle- that's good news,kinda' rules out the trans.