Hello I was trying to avoid making a new post but I was unable to find an exact answer to my situation. I wasn't getting the best fuel milage on my 2011 3.5 Ecoboost so I decided to change the plugs. The plugs we're rusty brown color and measured .40+ in gap. The truck has 73k miles so my guess is they were original. I replaced them with motorcraft sp534's I checked the gap on a couple and they were around .30 so installed them. Since I replaced them my truck has developed a light skip/misfire when cold it disappears when warmed up. It has thrown no codes. Also since I've replaced the plugs my truck surges under heavy acceleration and threw a overboost code p0234. Regular driving conditions the truck seems to drive great. I apologize if this has been answered but I couldn't find it. Thank you very much in advance.

Plugs I pulled looked like this.

 

 

I did replace just two boots that got stuck inside on the plug. The rest of the boost I reused. I haven't done the weep hole in the intercooler yet. I have considered doing the weep hole but I am nervous about doing it incorrectly. I brought the truck to my local ford dealer and they weren't able to get it in to look at it. Does every Ecoboost need the weep hole?

 

Is it surging under light throttle while the engine is cold then once it warms up the truck runs nice and smooth under light or heavy throttle? If so I am having the same issue, I have been reading tonight that cleaning the MAP sensors can help with this or possibly replacing them if they look bad. I tried replacing plugs and that didnt help...

 

Mine starts to surge around 3k rpms under a moderate to heavy acceleration, cold or warm it doesn't matter. The light skip/misfire my truck has is only when it's cold first start up. Once warmed up the skip/misfire goes away, it hasnt thrown any misfire codes. I looked at my map sensors tonight they don't look terrible but I might buy some cleaner tomorrow and try it.

 

Report back after you clean them, I read if they still have some discoloration after cleaning to replace them. I need to to pull mine out and check them as well.

 

I will let you know when I get them done. I don't think it will solve anything but who knows. Maybe I'll replace them since the outside of the sensor/screws that hold it in place are rusty.

 

Any luck with this?

I did end up cleaning all my MAP sensors and it cleared my problem!

 

I haven't had the opportunity to get them cleaned but I am anxious to get it done. Ive been doing more research and also read it could be my wastegate.