I am having major problems with my z. It shakes like crazy at idle, but idle doesnt jump around. The fuel pump has been going bad for a long time due to poor starting. If I prime it by turning key on and off many times it gets better and fires up immediately. The car has 79k on it. I was pretty sure it was the fuel pump due to my completely running out of gas (ya very dumb). But as of like a day ago it started the shaking. Anybody got any ideas or know whats wrong. I was gonna take it to my local dealer to get it diagnosed. Thanks, Michael

 

Why even bother to speculate if you know it's bad? Just change it and see what happens. Did you check fuel pressure at idle? If you check the pressure also check it after the engine is turned off to see how fast the pressure goes down. It seems to me if you had a fuel problem at idle, it would only get worse at higher speeds. Have you changed the fuel filter lately?

Your idle problem could be a sticky EGR valve or bad IAC. However, you also have to prime the fuel system so you could have a stuck injector. A little investigation can save you money and headache.

 

You suspect there's a problem with the fuel pump, so you need to troubleshoot it.

Like mentioned, check your fuel pressure- it should be ~43 psi after the pump has been primed, and it drops a few pounds at idle. You can get a guage at an auto parts store pretty cheap. If your pressure is below that, I would go after the fuel pump. Don't forget to replace the filter, too.