I have an unmodified (apart from a DV) my98 Sti. And somtimes i used to find at low revs or a a certain point on the throttle it would seem to choke and struggle, this problems seems to vanish then return, and it has now returnd and is become diffult when driving slow.

I have had my bottom end changed after my crank went, and also have had a replacement ECU due to that failing at one time.

Anyway just recently the flat spot has reappered and i am now just scratching my head. Has any one else ever had this problem?

 

check for clog fuel filter/sparkplug n ignition coil

 

98-00 cars are known to have MAF sensor problems. A flat spot in the rev range around 4k and inconsistent idle are the tell-tale signs. An ECU reset usually highlights it, or a diagnostic check at a dealers. MAF's are about 90 quid and worth replacing fairly regularly in cars from that period, as if it gets too bad the engine can suffer and the bills get huge.

 

thankyou for the replies, i must admit my idle has always been a bit erractic, and even so when the engine was changed and so was the ECU, the idle has always been the same, sometimes it like i think it will stall even though it doesnt. I have mever changed my Air box to a cone filter or anything i have always used the standard system on it , i thought the Maf usually went **** up when u put on a performance filter. ??

 

MAF's on 98-00 cars are so delicate many consider them an annual service item, they die without any external tinkering. If you do an ECU reset then it may highlight the problem, or get it plugged into a diagnostic unit.