Hey guys need some help.

Basically since replacing the inlet manifold gasket my rough idle has disappeared but I am still get this annoying engine stumble about 30secs-1min apart.

I put the dash in diagnostic mode and at 80degrees the engine stumbles(ISC sucks in some air & revs increase) & thermo fans come on until the coolant temp gets back down to 77 degrees.

The fans then turn off and the process repeats it self. I cleaned the earth for the thermo fan relays but that did nothing.

I disconnected the fans and let the temp run up to about 94 degrees and it didn't stumble.

Questions:
1) Thermo fans both coming on shouldn't cause the engine too stumble like the a/c compressor???

2) Is the ECU switching between lean/rich modes(open/closed loops) at these temps???

3) Would running a 92 degree thermostat stop this cycle from happening.

Try resetting the base idle, it will help stop the engine dropping so many rpm when the fans come on

Yeah ok will try that.

Just done some searching and found out the following;

EL thermo fans turn off once your doing 20km/hr, (unless your over 104.5 degrees then they stay on), they turn on LOW SPEED at 79.5 degrees(less than 20km/hr), ... exactly what the ECU is doing, so the cooler thermostat isn't causing open/closed loop drama's.

I searched this site for EL thermofan ecu settings but got that info from e-series turbo site...