jaycain

Hey guys, I have to say I appreciate all you've done here. It's helped me quite a bit with my 8.

I have a 1998 A8 4.2Q with about 141k on it, I was driving down the road taking my son to school (then headed to the fwy to start my vacation) and my RPM dropped. When I accelerated RPM's decreased more for a second then came back slowly as I lightened up on the peddle. Enough to get off the highway (about 15 feet luckly). I pulled onto a small street turned the car off and it hasn't started since. I have so far replaced the fuel pressure regulator, relay and filter in hopes but I thinking it's the pump. So I have a friend coming down to test the fuel pressure as I'm getting fuel (just don't think enough) and hoping that someone knows what reading I'm looking for at the rail (behind the fuel pressure regulator).

Thanks again for all your help!

Jay

jfrahm

Usually for this I start with a flow test, see if it'll flow a liter in 20-30 seconds. You probably have to crank the engine or the pump will not run.

You might have a CPS problem or something like that also, but it sounds like a fuel pump to me.

-Joel.

Kneale Brownson

Does the tach move when you crank the engine?

audinutt

almost certainly it's the pump, mine did it at about the same mileage and many others have experienced the same.

I was able to get a couple hundred more miles out of it by keeping it over half a tank, also might try opening the access panel and banging on the pump top with your hand, if the engine runs after this, the pump is dead.

-richard

jaycain

Tach does not move until it fires for a second then dies.

jaycain

Yep it was the pump! 800 later, almost running. My coolant reservoir sprung a leak. Apparently not my day to be on the road. Suggestions when changing your fuel pumps. Follow the instructions! There is an awesome set of All Data instructions on this site.

Thanks for all your help!