What can cause a flat spot?

[R32ONP]

ok so my car flat spots when its cold and it will flat spot untill it gets upto temp but sometimes it will flat spot for a while wen upto temp...then just randomly stop flat spotting and it will not flat spot any more... but when cold it will do it again..

sometimes it doesnt flat spot when cold

it idles mint as smooth as has no air leaks...

the TPS is set to 0.44 v and the idle switch works perfectly

is this a MAF sensor problem?

also my car cuts out at 6000 rpm (fuel cut) still driving me crazy the injectors stay off for maybe 3 seconds then come back on...does it at exactly 6000 in 2nd and 3rd gear..

it still does it at the exact time wether i do 7psi or 10 psi or 12 psi

any help would be muchly apreciated

car is a 1990 GTST type m with a RB20DET, 3 inch exhaust,std rb20 turbo and intercooler,ssqv bov,38mm wastegate,pod filter,chiped ecu

[ST240]

Bogs down like a mother at low rpm? Do you start running super rich and the turbo spools real quick? Mine does something like this. I suspect it's cuz my coolant gets too cold and it switches back into the warmup maps which i desperately need to tune. If the guy who "chipped" your ecu didnt switch the warmup maps i have a good feeling that could cause the low rpm bogging.

[Sil240]

What thermostat are you running??
If your running the Nismo which opens up at 60C or 144F.
And your car is cruising and cool you might be coming out of Closed Loop.

I've heard that Closed loop occurs at 165F.

Not sure though.
If you find out definitely. LMK

[rswails]

I have this similar problem. Mine has the flat spot symptom only when the engine is cold and the outside temp isn't that cold ( 60 degrees Fahrenheit ). During the winter, I don't seem to have the flat spot problem. It's weird. I have Nissan data scan which I highly recommend, and I decided to take a peak at things during a flat spot. What is happening is the timing is retarded. It pulls my timing back to 7 degrees. I have heard this is a knock sensor problem, not a coolant temp thing, but I don't know personally. It is very annoying. Please let me know if you fix it, and likewise for me.

[RustspecS13]

For the Fuel cut problem, Id look at the transmission sensor wires.

I had my RB20 in an s13, and I didn't hook up the 4th/5th gear sensors. And long pulls in 3rd-4th-5th it could cut out for what seemed like forever. I read in the FSM the ecu thinks its in neutral when that happens and it cuts power to protect the engine.

~Alex