Hello. I have had this car for 20 years and about a year ago the car started shaking on idle. I took it to Nissan center, they tested the engine, all running good. They changed the spark plugs, the car looked better for couple of days, and then went to the same. I took it to another Nissan center, they said it was bad injector. They checked it, injectors were good, but the main engine harness was not. Got a new one, the car looked fine, but couple more days and it's shaking again. Also, at high speed it looks like shaking more than normal, but not so sure about that, might be just me trying to overlook the issue. I don't know what else can I do to solve this. The start of the car is not the same every time. Sometimes it starts immediately and the rpm's stay down the 1000rpm and that's when it's worst. In the cold starts, also get a bit of fuel smell in the cockpit, I don't know if it's related with it. So, if anyone has any idea, please help me. Thank you

 

 

Did Nissan put the car on a Consult (or similar) diagonstics check? Have the connections to the PTU and MAF been checked for

corrosion and continuity? If you have an early style PTU they were prone to failure with symptoms you have described.

Early PTU type on left.

And welcome to the Club!

Welcome Julian and good advice from Andrew. Is it a UK Z?

Welcome to the club.

sure someone will help.

Hello . Thanks for the answers. The car isn't from UK. I don't know what kind of diagnosis they made, but the PTU on the car was early style, and with the new harness, I put a new style one. So, that was not the main issue, although they said the old harness was also not working well for sure. I've been searching a lot of things about the oxygen sensor, is there any chance that could be the problem. I tried to unplug it, and did not make any change, I don't know if that's what it's supposed

It is most lightly a bad Mass Air flow Meter,Or an air leak somewhere.Unplug the MAF and see how it runs after.

Hi and welcome to the club, Julian - I hope you get the issue sorted. We have some very knowledgeable folks on here and Jimmer is our resident 300zx-expert. Forget taking these cars to Nissan, nowadays all they know about are Qashqais and Micras.