Ian, i have told model reports to get ( or i would supply ) a HKS Super AFR i think this could help!...
Here is the write up on the item..
The HKS Super AFR is the very first airflow meter correctional device in the industry with a built in CPU. The advantage of having a built in CPU is that instead of making corrections to the airflow meter voltage, the characteristics of each airflow meter is inputted in the CPU so it can calculate the accurate amount of air flowing in. Since the correction will be made to this specific intake volume, the correction ratio of fuel will be precise and proportionally correct. The Super AFR is compatible with most Import and Domestic 12V, 2~12cylinder vehicles that utilize a hot wire, Karmen Vortex, or pressure sensor. The internal CPU allows it to be versatile and be utilized on many of the newer type airflow meters. Also incorporated in the Super AFR is the ability of idle air/fuel ratio corrections as modification progress and require further specific tuning levels. The response function, similar to the one in the VPC, allows for adjustments to the fuel settings upon throttle inputs to improve driveability and performance. The EIDS function is automatically programmed with the data from the initial self-learning calibration and automatically activated to correct sudden imbalances is air/ratios from discharge valves upon deceleration.
Air/Fuel Ratio Correction Function
Controls air/fuel ratios through airflow meter or pressure sensor
Range - 50% rich to 50% lean from the factory baseline settings
Output can be adjusted in 1% increments
Eleven points of adjustment between 650 and 8000 rpm, these points can be arbitrarily moved in 50 rpm increments
Response Correction Function
Engine response can be adjusted through airflow meter/pressure sensor
Range - 1m/sec to 100m/sec
Six points of adjustment between 650 and 5000 rpm, these points can be arbitrarily moved in 50 rpm increments.
First in the industry to offer this function in a simple airflow correction device
Idle Correction Function
Idle mixture can be adjusted 50% rich to 50% lean in 1% increments within the idle range (650 to 1500 rpm) from factory baseline setting
This adjustment is made independent of the other eleven points of mixture adjustments in the air/fuel correction function
Electronic Idle Stabilizer Function (EIDS)
This automatic function prevents engine stalling or stumbling in some airflow meter vehicles which use blow-off valves discharged to the atmosphere when throttle is released
Base of Adjustability and set-up
This device is very simple to set-up and adjust
The head unit is adjusted through three control knobs
HKS recommends tuning for this device be done on a chassis dynamometer with use of an accurate air/fuel ratio measuring device