94Q -trouble when car is idle

[Ted]

Yesterday, my 94Q ,with 84K miles, had a problem when I stop at a red light. The RMP started to move up and down between 250-1250 and then the engine stopped. I started the car again, and it works. This morning I had the same thing happened and the engine light goes on when I first started the car. But when I am driving, the car feels fine. When I got to work, I decided to start the car again, the RPM seems to be within the norming range between 600-750, but the need tends to move a little bit.

Last week, I had both the engine oil and transmittion oil changed. I live in the Bay Area, CA and I know that CA is changing the gasoline formula to make it enviromentally friendly. Does the new gas has any effect on how the engine runs? By the way, I do use super unleaded gas.

What do think the problem or problems are? This is the first time I experience this with the Q.

ThanksTed

[maxnix]

If they went in from the top to change your filter (i.e., it was not someone familiar with a G50 Q45), they might have dislodged your connections on your MAF.

Check these first per previous posts. Do you have TCS?

[Ted]

Brian,

Thanks for your reply. I show them work the the car. The guys change the filter from below. But what is MAF?

I assume TCS - traction control system. This is a regular Q45. I do not think this car has it.

Ted.

[carlos_knology]

MAF = Mass Air Flow sensor......

[landtodd]

MAF -- it's a grounding problem. Ground trouble confuses the ECU. The MAF works over a very, narrow range of low voltage, so it's particularly susceptible to infintesimal increases in ground resistance due to corrosion.

Wiggle the MAF connector when the car's running, and you'll either duplicate or eliminate the problem.

Car off, battery disconnected (safety overkill, but why not?), disconnect the MAF connector. If you like, lightly scrape the surfaces of the contacts, plug it all back up, and it'll probably run fine for a while. If the problem returns quickly, the replacement MAF connector has an external pigtail ground. Or so I'm told. I cleaned mine perhaps 4 months ago, and the idle has been rock steady ever since.