Here's another quirk...if we jack the rear wheels off the ground, we can accelerate up in drive ! But as soon as we take it off the jack and put it in gear, it dies ???

 

thhis is a turbo? so you have a boost gauge. what is it doing when you rev it in neutral vs rev it in gear ? idling, there should be a vacuum, eg, the gauge is maybe 30 deg to the left of 0. when you step on the gas the vacuum should go to zero, and as the exhaust pressure builds up, the turbo kicks in and you shoudl have positive pressure, eg maybe as much as 30 degrees to the right of 0.

you should do a fuel pressure test. with the vacuum line disconnected from the fuel pressure regulator, the fuel pressure should be 42-44 PSI, constant whether you're idling or revving up. with the vacuum line connected, it should drop by the idle manifold pressure, which is maybe -7 PSI so you'd see 36 PSI fuel pressure. if you give it gas, that will rise, if the turbo is working to get actual turbo boost you'd see more than 42-44 PSI (but thats unlikely without an engine load).

 

Just noticed with a timing light on it, brakes on....as soon as I put it in gear and barely, and I mean barely touch the throttle it goes FULL retard and stalls, I adjusted the throttle position switch with a meter not just by ear (click)

 

PS: On my last timing
retard post the timing starts at TDC !

 

I'd vote for the main fuel pump underdelivering... to add my two cents to all the chatter...

 

it would have to really be under-delivering for it to bog down coming off idle in drive.

the ignition timing on these cars is 100% digital, based on RPM, engine coolant temp, and not much more.

 

It acts like the problem is the Idle Control Sensor input to the CPU (which is nothing more than a micro switch) When you put the transmission in drive and barely move the Idle Control Sensor to where the micro switch barely clicks...the engine dies ! BUT NOT IN PARK OR NEUTRAL ??? PS: the Idle Control Sensor has been changed !

 

when the idle switch is closed, the ECU regulates the idle speed by modulating bypass air via the idle air controller (IAC). there's a procedure for adjusting this, see https://www.volvoclub.org.uk/faq/Eng...itchAdjustment

 

Thanks for all your input, the problem was two fold, I had a faulty in tank fuel pump and ALSO a faulty MAF sensor ! Back on the road, car just registered again and passed smog check !!!

 

I ended up replacing the In Tank Fuel Pump and the MAP sensor together and that fixed it ... Don't know if I had posted this fix before...