lumpy running on impreza 99 single cam ej20

[ilovemyscooby]

hay guys i recently changed the head on my impreza 99 ej20, and have just put it all back together but now it runs lumpy . leads and plugs r fine , and coil pack works fine . i have a code 31 throttle body position sensor. but the thing is ive altered this in many diffrent ways to see if the it make the car run better but to still no avail. even after error code has gone... air filter pipes are all on ok but it keeps spluttering on me any ideas please ?

Edited by ilovemyscooby on Friday 22 March 14:15

[ScoobieWRX]

Either a vacuum leak or you have some air leaking via the base of the inlet manifold, or you've not put your heads back right. Make sure MAF (If you have one), MAP, TPS and everything else is plugged in right, no broken connectors/wires etc...

[ilovemyscooby]

ok ... thanks for the tips will look into it