Tuning Problem???

[Trikes]

Hi Guys Raced my 01 Satria GTi in Hill Climb here in Tassie and before the meeting started I fitted my new Semi's and nicked off down the Highway to scrub them in. Most of the scrubbing in was done in 2nd. I was holding it at 3300 rpm and thats when I heard the engine burb burb burbing or da da da da daing. It was spiking about 400 rpm and did this costantly up to 4200. ECU is std 01 Mitsu. Never altered or tampered with or had a problem with in the past. Engine is stock std apart from Poddy and cold air intake that ran with last season. Exhaust is std apart from cutting rear muffler off and fitting straight pipe. Full throttle runs are fine as is the Idle except when I turn the AC on where it almost stalls. Always clean the MAF / ISC and Intake weekend before racing then daily drive to work for the week.

Any thoughts how I might fix this????

 

[evo-gsr]

Plugs...leads....coil packs ??

 

[evo-gsr]

Check all the easy things first, change one at a time to eliminate each.

 

[BMGTZ]

that is about the transition point for vacuum to boost. so the ecu cant keep up with fluctuations from the afm as it is either side of the zero point.

mine do the same...forget it and drive around it.

 

[4piknup]

Not meant to clean our maf. The solvent does something funny to them. Plenty of guys do clean them but it says on the bottle not for the mitsi maf

 

[evo-gsr]

Isnt this car NA ?

 

[Trikes]

Yes NA.

 

[evo-gsr]

I thought so. My suggestions still apply then.