I have hesitation from idle and surging revs when cold from my 91 2+2 NA Auto; Heres whats been done so far to no avail, can anyone suggest something else for me to try?

 

New Fuel Filter, Checked and adjusted ignition timing and idle speed, Checked AAC Valve, reset TPS, tested electronic fuel control pressure curcuit, tested O2 sensors, tested fuel and water temp sensors, Cleaned all connections. Checked and cleaned throttle bodies, Full carbon injector cleaning and new connectors, Checked Fuel purge soloniod. New Plugs NGK 11B's, Rebuilt airflow meter, new Valve timing unit, new cambelt, new head set, new piston rings, new bearings, cylinder heads machined, new hoses, new trans cooler, new oil filter, Rebuilt trans with shift kit, All electrics and ECU checked, total cost $9000 NZ!!!!

Still hesitating and surging, any ideas guys?

Clean/replace temp sensor and possibly use a Consult/Techton to see what the O2 sensors are sending out around those revs.

Have you tried synchronising the throttle bodies?

They are a common cause of hesitation from start.

If they are misaligned, then one will open before the other and

there will be different ammount of air on the 2 sides of the motor.

 

The synchronisation procedure is described in the service manual.

I have also made posts on the subject previously,

describing my way of adjusting them.

Do a search.

 

Good luck!

Let me know if it helps.

Maciej