Rough Idle/Hesitation/Backfire

[bans25]

Old thread but I am working through the same issue with my car... What did this end up being on your Z?

[jeasen]

On my car the issue was with the ignition coils. I looked back at my posts on this thread and found that one of the coils was dead and others were out of spec. I replaced the coils with new ones that were in spec and the car ran fine. If you look back on this thread you can find the specs for the coils. Do not just buy new coils and leave it at that. Test them before you buy them. Many new ones are not within spec and should not be used in our application. Good luck with your problem.

P.S. Being our coils are under the plenum and subject to a lot of heat and cooling it is important to start with good coils. Hope this helps.

[Pete]

Most common issue for this is in our cars is spark plug wires,fuel injectors.

If you take your plenum off i would replace wires and spark plugs and while under there ohm injectors,check for leaky injectors and check coils.

If you "Search" on here you will find all the procedures.

On the spark plugs you don't need the fancy plugs that cost $10-$20/each just regular resistor plugs are fine $2each.

Pete