l have a 1990 nissan 300zx, high miles 170k but very well taken care of.Recently it started acting up.Intermittent running rough (cylinders going down) and check engine light coming on.Again intermittently.Upon start up the car works as it is supposed to for about 5-10 minutes then starts misbehaving.l took it to my local nissan dealer for diagnosis and they tried to tell me l needed to replace all six injectors, the wiring for them and both oxygen sensors.Which to me is sort of like saying ''hey, l have no idea whats wrong with your car but if l replace lots of parts it will probably fix it.... also give me three grand.''

What I am hoping for is someone who is familiar with these cars to give me an Idea of where to start looking.l have some idea but am but will leave them out so as to get a more uninfluenced response.

Any help would be appreciated... thanks

Run a diagnostic check on the computer. Heres how to do it and how to read it. Also a few tibits on maintance items:

http://ttzd.com/tech/diagnostictech.html

Your nissan dealer is exactly right. However run a compression test first because what is next is going to get expensive. Compression test is ok? If ur mechanic is going to remove the intake plenum to replace one or two 19 year old injectors & another fails? Do all six injectors & all the electrical plugs if u can afford it.19 year old o2 sensors that old should be done just because it will make the fuel mixture system work better. If l had the plenum off l would also service all the coolant hoses PCV valves hoses & air tubing clean out the EGR system & replace all the fuel lines with new high pressure fuel hose & a new fuel filter. Now here is something that gets overlooked the $185 dollar Knock sensor is just another 8/10 bolts & intake manifold removal away But the two intake manifold gaskets cost almost 70 dollars each. Actually ur dealer is not looking past the injectors & connectors that r needed & recommending the other stuff u should do while ur in there. How about a new timing belt? water pump? clean debris out of the radiator? The list can go on & on. 300zx r great cars if properly maintained. Expect to spend around $3,000 on ur car this visit & another $3,000 for timing belt upper suspension links & track control rods & alignment issues next time & then Shock struts? Radio speakers new carpeting door gaskets T top liners 300zx will drive u to the poor house but what a fun ride getting there

l wish l knew what to tell you. But l don't. But from your avatar l really get the sense that you are attractive, and wear laurel wreaths well. So my answer to you is this: try and focus on the positives. Now please give me best answer.

PS hope things work out re your car.