308 starts running rough poping and jerking when gets hot

I'm not as familiar with the 81 version of the Bosch FI... but seems to me it may be an air leak? if its good cold, but started to act up when it gets warmer - could be a hose getting warm and cracks opening up? .... I would think something temp related. I'm not sure if they have an Aux air valve under the catch tank or not. my QV would act that way and it was the air hoses. OR something electrical... but again cold to warm ... would make me think hose cracking as it gets warm...

 

I would also consider checking your fuel pressures to make sure they are in spec. In particular, confirming that the WUR (warm up regulator) is appropriately increasing the fuel pressure exerted on the fuel distributor control plunger as the car warms up. The WUR on Kjet and Kjet w/lambda cars will have a "cold control" pressure specification which is dependent on ambient temperature at start up as well as a "warm control" pressure specification which in influenced both by 12 V that is applied to the WUR plug after start up along with increasing engine bay temperatures.

The 81' 308 GTSi (NA version) was equipped with the 0438140083 Bosch WUR. The cold control pressure specification for this WUR will depend on initial ambient temperature. For example, at 70 deg F, cold control pressure for the -083 WUR should be about 2.2 bar. As the car warms up the control pressure should increase to about 2.7 bar. This is the so called 'warm control' pressure. When vacuum is applied to the -083 WUR the warm control pressure should increase further to about 3.5bar.

Hope this helps. Best of luck in getting things sorted.

 

Apologies, I meant to update my response with screen shots of the actual fuel pressure spec sheet for the -083 WUR including the cold control pressure vs. temp curve. Here it is:

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