Gen 3 3sgte hesitation bogging issues

I am out of the blue having hesitation and bogging issues after a few days of heavy rain. The symptoms are very similar to http://www.mr2australia.c...lay/m/tm.aspx?m=125254 .

It is a gen 3 swap running a gfb mbc, arc intercooler, ko racing intake and 3 inch catback exhaust. Everything has been running fine for a while now, never had idle issues or boost issues.
I had to take it to uni on a day of heavy rain, as i got back in my car and turned over it behaved normally, however while warming up idle dropped to around 500rpm and was threatening to stall without a little gas. It eventually got back to 900-1000 and i didnt think much of it. I got to the shops turned my car off went in for 15 minutes and came back to the same thing.

This time, when driving it felt almost like major turbo lag i could hear the turbo spooling but it was like there was no pressure and it wouldnt let me put the power down. Next gear hesitated abit then boom boosted like normal. I kept driving for a while and it seemed to go away.

I have checked all hoses and tightened all couplers, since then it hasnt dropped idle however it still hesitates then when it comes on it feels like its free boosting.

Boost leak? Knock sensor? Vtv? Coolant temp sensor? Map sensor?

The thing is my girlfriends s14 has the exact same issue which started similar, but now happens pretty much all the time.

Hoping it is something simple like a vacuum boost leak but i thought being the sr has an afm and this has a map sensor i really dont know where to start now,..would like to avoid replacing every coupler and clamp if possible but seems like next thing on the list.

Any help would be greatly appreciated,
Thanks and regards,
Abs

Guessing.... based on your girlfriend has the same issues in a s14.
Do you both buy fuel from an old looking (dodgy cheap) service station that is down the bottom of a hill? 
Try dumping your fuel out of the tank, filling with fresh high octane fuel and fuel treatment.
 
Guessing... based on under boost its ok.
When was the last time you did a service on both cars of fuel filter, and/or replacing the fuel pumps?
 
Guessing... based on a mr2 ECU.
Get the ECU fault codes, there are online guides....what does the ECU tell you? 
 
Guessing....You go to uni, I remember those days where funds was tight.
Do you get time for your servicing of oil, oil filter, cleaning your throttle body including your idle up valve etc? Get your service centre to get the probe in your exhaust to check your air/fuel ratio under idle and cruising and acceleration.
 
 
 
 
 
 

Thanks for the replys guys

@justace
Il try disconnecting the leads and spraying them with contact cleaner. I sprayed abit around the dizzy and left the engine lid open in the sun for a while but to no avail.

I have tried bridging the te1 and e1 terminals however didny get any flashing error codes, so im guessing nothing has been stored?

@tonymr2

Services have been up to date every 5000 kms synthetic oil and filter, as well as copper plugs (both mr2 snd s14). I recently did the valve cover gasket and cleaned the throttle body up (for the mr2) and only ever used 98 octane bp ultimate. When the swap was done i put in a modified denso supra jza80 pump (i think the brand was kyosan) I thought it may be fuel filter too as i havent gotten around to replacing it, i will check that out. Not too sure what you mean by servicing the idle up valve?
Is that the plug on the map sensor side of the tb or is that the tps?
Il look into getting the a/f checked, do most places do that or is it more of a only performance mechanics?

The s14 on the other hand is very "sr20 spec" so theres alot to get through to narrow it down. So far have changed plugs, checked for boost/vac leaks and tried unplugging cold start. I made sure to disconnect afm and sprayed with contact cleaner.

@artymr2

The plug chambers themselves seem to be dry and clean ever since i did the valve cover gasket, however i will try compressed air just incase.

Guessing best bet would just be to replace ignition components however genuine toyota gen 3 stuff isnt the cheapest. Was hoping i would get an error code to narrow things down, but the thing that confuses me the most is it only happens sometimes, usually on cold start and after a few kms it goes back to normal, which was the same as the s14 which now does it all the time.

Thanks for the input,
Abs