s13 ca18det idle and driving engine problem

[pktheo]

Hi All

Im new to this forum and i have spend days looking for advice on what could be causing the problems on my car.

When its hot the idle varies by about +-80rpm and it makes a popping noise from the exhaust, the engine is also shaking quite a bit i'd say about 1cm of movement you can feel it from inside the car whilst driving it hesitates at 2500 and 3500 just before boost, i'll give you as much info as possible.

I bought the car in feb 2011 with 223000kms on the clock it had had a full rebuild at 200k and in april 2011 wrote off the front end (only stuctural engine wasnt touched) in an accident, rebuilt the front end, and made the folling modifications, fmic, t28bb from s14, alu rad, hks back box with 2.25" straight through system, ported ecu with stage 2 chip, added gauges and a few other bits, once she was back on the road again had no problems apart from the turbo over boosting but then this problem started so i changed the plugs for ngk iridium hr7 and still the problem persists, i thought it might have been the ecu so i reverted to the original one that came with the car and all was well but as soon as the car was hot started the same thing again.

I dont know if the timings out or the mixture is wrong or if its something maybe more?

if anyone can help me it would be greatly appreciated.

Many thanks

Theo