01 Yukon Stalls Shortly After Starting

pugandsandy · May 14, 2009

I have a 2001 Yukon which seems to stall shortly after starting. This is usually within a few miles of home, and it happens when driving slowly...especially when turning (such as into a parking spot). The car has about 105,000 miles on it. This was happening about a year and half ago. The mechanics replaced fuel pump (and filter, I think), and the problem seemed to disappear. I'm guessing it's the same problem, but I haven't taken it back in to have confirmed.

A simple search on google seemed to suggest that this isn't uncommon. But I don't really want to spend the money on another fuel pump and the labor, since it hasn't been but about 15-20K miles since it was replaced.

Any thoughts?

Thanks.

bill190 · May 14, 2009

These days there are all sorts of "gizmos" which can cause idle problems. The best and least expensive thing to do is test all these things to find the exact problem(s). Then you are not "guessing" and replacing parts which don't need to be replaced.

If you want to learn to work on your car yourself, I would suggest getting a factory service manual set from your dealer (my set is 4 books). Then get an electrical multimeter and learn how to use it to test for voltage and resistance (ohms).

Search google.com for multimeter for instructions. Keep searching for this until you find something basic and easy to understand. Multimeters can be used for simple tests as well as complex electronic tests. For automotive use, most tests are simple ohms or voltage. So if the instructions look like Einstein wrote them, ignore that and try another web site until you find something easy to understand.

With my service manual set, the fuel and emissions book is the best for "gizmo" testing. This tells you what to test based on the problem the engine is having. Then tells you how to test each device.

Outside of that, can you place your foot slightly on the accelerator and then the engines runs fine? And in all other situations the engine runs fine except when you have your foot off the accelerator?

If yes, then this could be a problem with engine idle. When the engine idles, the throttle is completely closed and the engine computer adjusts the idle via a valve called the IAC valve. (This information is generic, your vehicle may be different as they like to change things around!)

Anyway the engine computer gathers information from various sensors, then adjusts the IAC valve to allow more or less air into the engine to adjust the idle.

If the engine computer is getting the "wrong" information (from a malfunctioning sensor), then it can't adjust the idle correctly!

Or the computer may not know it is at idle and should to get to work!

Or the IAC valve could be malfunctioning and the computer is trying to adjust the idle, but it can't make the valve move.

Anyway there are all sorts of sensors for temperature, oxygen in the exhaust, position of the throttle and if at idle or not, air pressure, etc. It is the combined input to the computer of all these sensors which allows the computer to adjust your idle speed, fuel, and timing so it runs just right at idle.

Also if the problem is in fact with the fuel system again, these books would show you how to test the fuel system to determine where the problem is. There is a lot more to it than just the pump. Here is an example...

http://www.asashop.org/autoinc/june98/techtotech.htm