Weird Cutting Out Problem

[rb180]

Did a search and didnt really find much(Everyone says thats, so maybe i didnt search hard enough hehe)

I have a 90 model r32 gtr and was driving on the freeway. Cruising at ~100 km/h and was off boost. Then came up to a slight incline in the road so i accelerated a little to keep my speed at around 100 km/h. With the acceleration the boost pressure is now positive but only making 1 or 2 psi as im only slightly pushing the throttle to maintain the speed going up the slight hill. The car then starts 'cutting out' and spluttering and the Cat temp light on the dash lights up. Then i slowed down to about 80 km/h and down geared to 4th and hit the throttle and it boosts smooth and doesn't miss or cut out or splutter. I then go back to cruising at 100 km and come up to another hill so i accelerate abit to maintain speed(cruising at 2 or 3psi) and get up the incline and the same thing happens again. It cuts off and splutters and the Cat temp light comes on and goes off a few seconds after i get off the throttle.

The car drives fine around town and doesn't misfire or cut out while cruising or at WOT.

This has happened to me before on the freeway and i didn't think anything of it (Cat temp light didn't come up that time).

It only seems to happen when I'm at around 100 km/h and really slightly come on boost and try to maintain the low boost(2 or 3 psi) as i cruise.

Its abit hard to explain in words. So if anyone has any ideas or does understand what is happening any help would be appreciated greatly.

I had a turbo back exhaust put on a few months ago and I'm guessing the cat temp sensor was retained in the after market high flow cat because otherwise it wouldn't come on at all if it wasn't connected.

Also Have standard Computer so its not the power fc showing high knock readings.

TIA!

[rb180]

It is actually abit similar to the problem this guy had.

http://www.skylinesaustralia.com/forums/in...howtopic=102476

When it was cutting out i gave it more throttle and the boost wouldn't go above 10psi..

[bludger]

hey guys iv got the same problem also,the light came up looked like the cat converter with those little heat lines on it???

any ideas what needs to be done