I just had my 94 Nissan Pathfinder V6 tunded up. It went in running fine. It came out running rough after changing wires and plugs. Distributer shaft was loose. Tightening a screw in the shaft solved the high speed roughness, but now it won’t idle at a steady low speed. In fact it stalls at stoplights.
Your timing is probably wrong now.
Mechanic says the distributer position was unchanged. the screw was just a set screw. he also says the timing is computer controlled and can’t be adjsuted - I’m not sure on newer cars…
Has the mechanic given up? He must keep looking for and correct the condition he caused.
I actually liked it when it became impossible (on some cars) to adjust the timing,so many people with the “could the timing be off question” could be told ,no.
In the early days of emission equipment being able to move the timing around was valuable,but then the Feds took idle mixture,idle speed and then ignition timing away, some people used being able to adjust idle mixture,idle speed, and ignition timing as ways to avoid fixing the real problem,but when the real problem was in the design of the emission equipment you did what you had to do.
The timing issue need to be revisited. As far as I know no car has ever been built that uses a set screw to tighten a distributor shaft. However, there may be a set screw on the rotor and this could be what is mentioned.
As to stalling I would say either a vacuum line is loose (probably not) or the timing is off. The timing can be adjusted. The sticker on the hood spells out the exact procedure for checking the timing and this sticker takes precedence over anything that is stated anywhere else.