Simply put, PLA and ABS should not be mixed into a filament.
The most common issues most printers experience, such as delayering, warping, etc., are addressed completely differently based on the material you are working with. There are many examples of this, and I will attempt to go over some of the basic ones.
You will have extreme difficulty getting proper layer adhesion. Assuming you have a level, flat, semi-coarse (helps) surface for the first layer, the recommended heated bed temperature is 70C for PLA. With ABS, you will experience warping by the 5th layer at that temperature. ABS prefers 110C for a heated bed, and 80C for a heated chamber (personal experience for most reliable results).
Next issue is going to be delayering and stringing. There is no happy medium! Matter of fact, the number of issues even attempting this is almost too many to list. The quality will be complete garbage. On one hand you will have delayering, warping, and jamming of the ABS when set to PLA specs, and stringing, leaking, etc., when set to ABS specs.
I hope this helps.