K8 Is stuttering badly when at normal driving temp

[cooknl]

Hi Guys, I am a newby here, my name is Rob Cook and live in Holland.

I have a 94 MX-3 GS V6 1.8 ltr. or K8 as you guys know it.

Problem is as follows,
Cold start 1700 rpm and slowly comes down, after a minute or so it drops to 750 rpm when i drive the car when the temp is below normal, it runs great, no probs at all.
When it reaches half way on the temp gauge is when the s--- starts, it starts bucking and hardly any power.

Have replaced:
plugs and wires
cleaned airflow meter and gas positioner valve with the throttle cable on it.
installed HEI module and reset ECU.

I checked all kinds of stuff like TPS and steppermotor all seem fine.

Has anyone got a clue of what my problem might be like maybe lambda sensors or temp sensors or???

Any help greatly appreciated

Rob

[mowambi]

Mine did this when i had a MAF leak, do you have stock intake or did you make one?

[shameem]

Check for vaccum leaks
Check Coolant temperature sensor
Check oxygen (lambda) sensor
Check ignitor module