What makes a car run rough and rich when cold but, smooth out when warmed up ? Car in question is a 95 Z A4 with mild mods.

 

Carbon build up, high mileage

 

O.K. found time to replace plug and wires. Plugs looked loaded up and 2 questionable wires. Car runs extremely rich when cold and feels like it wants to stall sometimes when stopping. Stumped once again by the mighty LT1. any thoughts sees ?

 

Take a look at your o2 sensors then if it still persists change out the opti, but before all that just have autozone scan it for free.

 

the engine light isn't on. The car runs rough when cold so, why look at the o2 sensors?

 

The answer to the riddle is mass air sensor.