I've been running through the many post in the search having to do with misfire, studdering, fuel cut and just can't seem to nail down my problem. First off let me start off by giving you my current setup.

Howell 2.2L stroker
P&P head
8.8:1 Comp
Crane 14's
Hahn S16g with front mount
Venom mani
Portfueler
Crane ignition
Msd Coil
Etc.

Pretty much everthing for the built motor from internals to Full 3"exhaust.

The problem:
Anytime I go past 1/3rd throttle around 3 psi or higher, the thing starts studdering like the 2 step has kicked in, only not nearly as harsh. It will do this at any rpm. The engine will still boost when the problem is occuring and the wideband will read around 11.5-13.0 and the egts dont go over 1300 deg F. The car can still make as much as 15 pounds and still have good afr's. I have been fighting this for some time now and have done everything I can think of. I will probably leave something out due to just being to frustrated with this thing. Here is a list of things I have checked or replaced.

Map sensor
Also checked to see if missing link was working properly and yes 4.51v at all boost levels even with 80psi from an air compressor. So its working.
TPS changed and checked out ok
Crank and Cam pos. sensors
Upper O2 Sensor
Wired ignition back to stock
Plugs
Wires
Coil
Fuel filter
ECU
Unplugged knock sensor
coolant temp sensor and checked out ok
Fuel pump is working fine. Well both are Walbro and Accel
Hooked ignition up stock eliminating the Crane

I am pretty sure I have checked everything. Maybe not. Just ready to give up. I have waited to long to get help. I have had this car for a long time and been boosted for like 6 years. I have rebuilt the motor two other times so I am not new to this. Anyways, sorry just fed up.
Like I said it is like a studdering or misfire on all cyl. I have hooked up a snap on scanner and the only thing I can see that is weird is that at an idle the scanner says its in open loop. No codes other than the codes for coil a and b failure but have searched and common for ignition boxs.
The car idles perfect vaccum is good, compression is good. Fuel cut was on my mind for the last few days but map voltage is good. I dont know if it is harder to diagnose with the Portfueler runing those additional four injectors no matter what. Plugs look ok Maybe a little lean but still brownish. Hard to tell with the studdering. But I would think If I was loosing Spark they would be Black. But by the time I get home and kill it to check them, Well. So any help would be greatly appreciated. I have been coming to this site for a long time and you guys are the best source of knowledge out there. If I cant figure it out I think that I will try going MSnS. But I wanted to get used to tuning with the portfueler. I have always used the SFMU setup. Sorry to jump around so much, but I am tired and just plain sick of this thing.

10 bucks says its your missing link.

i am sending out a FCD to another member on monday morning, if you want one, i can send one to you too. its a cheap fix. PM me if your interested.

we have seen so many of these posts and everyone says the ML is fine, they put in a FCD and they are good.

well like i Said the voltage never goes above 4.51 volts. but at this point I am willing to try anything. I have everything to make a FCD, The three wire kind. 1k pot and 2 1N914 diodes. Is that correct? cause if so then I will just make it up and try it today.

Yeah make one and see what happens...

well I built and installed the FCD and still nothing has changed. I set the voltage to 4.63 and got the same results as before. I will try a lower voltage but am skeptical.

Sounds like you might be fouling the plugs out or running so rich/lean your losing spark. Check your coil, Check the gap on the plugs. 11.5 at 15 psi is way to rich, adjust to 12.0.

You could even have a small spot right as you enter boost where your going lean. It could be so fast that you cant see it when driving buy you should be able to see it in a datalog.

You might have a weak coil.

Its not your missing link, thats obvious.

well I have tried leaning and richening up the whole fuel mixture by like 30% both directions. The plugs never look rich but, I will try and log and adjust accordingly. I got it at one point to like 12.5 to 13 all the way through and still the same. It seems to be a little better after 4000 rpm's. So according to other posts that leans more twards crank sensor, but I have put 2 other than the stock one. They are ones I got from NAPA. If I cant get this figured out, I will be getting ahold of you Terry for a MS setup.

I bet its your port fueler. Looked at the software lately?

Originally posted by DarkOne
I bet its your port fueler. Looked at the software lately?

Well I guess not. I Just started using it about a month ago. I picked it up used. I will have to check the version tomarrow.

They update the software Dino?

You need to get good witht his before you go MSNS. The MSNS, because of all the added functions, can be even more difficult. If you want MSNS, want it for the added capability, not because it might be easier.

Terry

That is not why for the MSnS. I am going that route eventually. I agree on getting it fixed first. I went to split second's site to see if they had any info on an update. I guess I will have to call Hahn to find out some info.

No, but it stores a map and some basic settings for fueling just like anything else. it's only "plug and play" because HRC programs a base map for you.