Expedition runs terrible after 1/2 throttle

[mangus64]

Folks, I'm battling a heater problem in another thread but another problem my Expedition currently has is that it cuts out, misses badly if given over 1/3, 1/2 throttle. Runs fine up until then so one can basically baby the thing along. However, encounter a hill and have to give it some throttle and it falls on its face.

If one babys it up to 65, it'll run smooth up there but again if you have to give it some throttle it falls down bad.

I changed the fuel filter about a month ago. Would the EGR valve possibly be to blame? I took it off a couple weeks ago when I was cleaning the IAC for an idle problem. I lost the gasket between the EGR valve and the throttle body so I bolted it back up. Doesnt appear to leak but maybe it does? Is this vacuum at this connection, where the gasket sits?

The gasket dropped down under the throttle body and hasnt been seen since

On a carbureted engine I would say it has a lean condition hence why it stumbles and bumbles. I checked all the vacuum lines I could see yesterday for leaks. Intake leak?

No CEL through all of this either, or since I cleaned the IAC.

Thanks for any help guys.
Mangus

 

[02Sexpedition]

i have a similar problem with mine as well. anything over 3k rpm's and its like it just doesnt have ANY power! once it gets up past 4500k rpm's it has its pickup back. Almost like it has a power band and doesn't kick in till it gets up in the rev's. It really sucks ass! It doesn't have much power low end either. I dunno what could fix this. Any suggestions will be appreciated.

 

[panda24619]

theres a sticky thread on here talking about a vacuum leak at the elbow behind the TB. check out the thread and then the elbow. those are the same symtimes i had and when i fixed the elbow all gone.

 

[panda24619]

http://expeditionforum.com/showthread.php?t=4913

there you go.

 

[mangus64]

Thanks yep I saw that and checked that early on. Cleaning my IAC fixed the rough idle. Mine kind of does that as well in that about 4K-5K RPM the power comes back and it runs clean.

 

[02Sexpedition]

i just had the intake plenum gasket replaced and the elbows about a month ago. shouldn't be the issue with mine. And yeah, it did the same thing before that was replaced. I dunno what it could be. I know I hate it! BAD!

 

[panda24619]

is it still doing it. then clean the maf. some times it gets clogged up. i clean it every oil change. and my air filter.

 

[tmajikman]

Could be a clogged fuel filter or your fuel pump is not pushing enough fuel pressure, or maybe your fuel pressure regulator is bad.

 

[ssbroly]

That almost sounds like a bad plug or coil. I had the exact same issue going up a hill or when the engine was under a load. Have you guys checked those recently?

 

[DR3W]

Try the GOTTS air intake. It should free up some power, espically at higher RPM's. Maybe try this, because its like $15 & reversable.

http://www.fordf150.net/articles/idx.php/0/021/article/Gotts-Intake-Air-Intake-Modification.html

 

[Scewloose172]

i have a similar problem with mine as well. anything over 3k rpm's and its like it just doesnt have ANY power! once it gets up past 4500k rpm's it has its pickup back. Almost like it has a power band and doesn't kick in till it gets up in the rev's. It really sucks ass! It doesn't have much power low end either. I dunno what could fix this. Any suggestions will be appreciated.

Hey, You and I have exactly the same problem...When I pass someone it drops into passing gear and makes the proper RPM's but no "Go". I haven't seen you bring it back up so I was curious if you solved it or not?