What causes the Q 's idle to fluctuate up and down?

[SUB ZERO CAR FANATIC]

Hello Chris. A couple of things come to mind. You say it idles fine until it warms up so I'd agree with a previous poster that there could be a leaky vacuum (emissions) hose. If its happening about 20 minutes after starting the engine that's about the time the EGR system starts kicking in. Get a can of brake parts cleaner and spray around all the hoses and intakes listening for idle changes. The entire system is under a vacuum so any leak should suck in the fluid and change the idle.

I'm having injector issues on my 90Q from the PO using a fuel rail that had been in a salvage yard for an unknown period of time (years?). Even though all of the injectors now ohm good, two are still plugged even after a BG injector flush at a local shop. If your fuel rail was sitting around with fuel in it for any length of time (3 yrs?) you may be having the same problems. Unless you've got a laptop and consult, you're going to have to unplug one coil at a time and look at the RPM drop to narrow it down to a cylinder. I haven't seen any FI injector resistance measurements posted either. Tell us what you've got.

At this point if you own a laptop or have access to one, and plan on keeping your Q (I know you do), a good investment for you might be a consult cable and software for about $130. It would take a lot of the guesswork out of the troubleshooting process. Good luck.

Mike, exactly what is a consult and what does it do? How do you go about getting one? I assume it has to be a laptop because of mobilitypurposes, am i correct! If it takes the guesswork out of everything itwould be worth its weight in gold!! THANKS FOR THE TIP MIKE!!!

[Haitian_King]

Mike, exactly what is a consult and what does it do? How do you go about getting one? I assume it has to be a laptop because of mobilitypurposes, am i correct! If it takes the guesswork out of everything itwould be worth its weight in gold!! THANKS FOR THE TIP MIKE!!!

A Consult is an interface that allows you to connect to the Q's computer. You can get everything from it. You can record all sorts of data. You can turn cylinders off at will and monitor the engine internals in real time.

I'll be getting one myself. Blazt.biz is where you can get the cable and software. Then you can connect it to your laptop.

(I've never done this, I might be wrong. This is what I can remember from other Consult posts.)

[SUB ZERO CAR FANATIC]

A Consult is an interface that allows you to connect to the Q's computer. You can get everything from it. You can record all sorts of data. You can turn cylinders off at will and monitor the engine internals in real time.

I'll be getting one myself. Blazt.biz is where you can get the cable and software. Then you can connect it to your laptop.

(I've never done this, I might be wrong. This is what I can remember from other Consult posts.)

Ive definetly got to invest in one of those.Sounds like $130 well spent!!