Engine stutter (loss of power) between 4-4.5k rpm only

[hahaitzskippy]

i have had this problem in the past with other cars and have this small issue with my m10...

have you checked the timing? for some odd reason, i changed the timing on my m10 and it kinda worked "like a bandaid patch"

i changed most of my fuel parts out, regulator, pump, sending unit and the problem is still there (just slightly)

in the past i dealt with the TPS and it sorta of resolved the issue as well... letting me go to a higher RPM but NEVER WOT.

have you tested your AFM yet? i havent had the chance to do that on my car yet.

but if you do, let us know how it goes

[rcfanatic]

Does the econometer react during an event? If so which way does it move?

Cruising at 3k rpm in 2nd gear the gauge reads ~12 mpg. When I do a WOT pull it steady falls and at 4k pauses at 5 mpg until I regain power and it continues on to 0.

[rcfanatic]

i have had this problem in the past with other cars and have this small issue with my m10...

have you checked the timing? for some odd reason, i changed the timing on my m10 and it kinda worked "like a bandaid patch"

i changed most of my fuel parts out, regulator, pump, sending unit and the problem is still there (just slightly)

in the past i dealt with the TPS and it sorta of resolved the issue as well... letting me go to a higher RPM but NEVER WOT.

have you tested your AFM yet? i havent had the chance to do that on my car yet.

but if you do, let us know how it goes

The ignition timing is controlled by the DME and valve timing can only be changed by installing an adjustable cam sprocket. Either way I don't see how either could affect this small rpm range.

[rcfanatic]

Another Update:

Today at WOT it stuttered 3500-4500 rpm, recovered, and then again at 5-5.2k rpm. Engine almost warm.

Also it will now do it at half throttle or maybe even less. The problem is definitely getting worse.

Another thing, twice over the last 3 weeks the engine simply died while idling. Very smoothly, as if someone turned the ignition off. There has also been a few times when it completely fell on its face while accelerating, as if there was a momentary fuel cutout.

I don't understand, everything in the fuel and ignition system is new or refurbished within 3 years, except the fuel pumps.

Could an AFM cause all of these problems and its health degrade so quickly?