Hesitation at low and highway speed
 

My 2000 S80 non turbo recently started hesitating at low speeds. it's only for a split second though. Usually when starting from a stop light or rounding a corner and stepping back on the gas. Just drove 4 hours to Spokane on the interstate and noticed intermitent hesitating with the cruise on at 75mph. Just enough to feel your head drift forward for a split second, then back to normal. No check engine light or anything

Anyone have advice? Fuel related? Electrical?

Thank you,
Kevin

i would guess fuel system first maybe pump maybe filter. i know when my pump started going out i got no lights whatsoever. for some reason one day if i went below a half tank id lose fuel pressure and the car would die out. no lights or anything in the cockpit. changed sending unit (fuel pump assembly) and all was well. however before spending a few hundered dollars on that id confirm somehow.

explain in detail, like when you hit the gas on the highway to overtake someone noghing happens ????!?

Hi andrei333, When I have the cruise set at 75 on the interstate it feels like it is loosing power, hesitating, for a split second. Like when you aren't using cruise and you lift on the gas pedal for a second, then push down again. It also does it when I am rounding a city corner and accellerating back to 25 after turning the corner.

I'm going to remove the throttle body this weekend to see if it is dirty again. Also going to change the fuel filter.

Update....cleaned the throttle body last weekend. Wasn't that dirty but easy to do and can't hurt. Plus I coached my 19 year old through it so was very cool. Anyway, after I cleaned it earlier this year I installed a PCV filter system between the PCV box and the air intake before the throttle body. I thought this would help to keep the TB cleaner, which it obviously has. When I checked the filter I found it completely full of a combination of water and oil sludge. I think what may have been happening is since the filter was full, the intake may have been sucking in minute amounts of the oil/water causing an occasional momentary hesitation with the engine.
The thick sluggy oil is typical in the filter. I think the water has come from condensation due to the extremely cold weather we have been having in Montana this year.
If you want to see more information on the concept behind the filter check out www.condensator.com. I put one on my 97 Yukon many years ago for $170. I couldn't believe the gunk it caught. So I wanted to put one on my Volvo after the factory PCV box got clogged. This time I saved ALOT of money by building my own. All from parts I got at Home Depot! For the filter itself I used a standard compressor filter built to remove water from compressor air lines. The only downfall with my self built is the catch container is smaller.

Hi kevmcrae,
My 2001 S80 2.9 had similar issues a couple of years ago and also very recently. Turns out the electronic throttle module (ETM) fails on these cars. 2 yrs ago, dealer cleaned the ETM and the problem kind of went away. I heard the ETMs are warranteed for 100,000 miles or 10 years. With recent problem, I took mine to the dealer again, they checked for codes, said the ETM was faulty and then replaced ETM at no cost to me (apparently an expensive part). Car runs much better now. Not sure if this could be the problem with yours, but worth looking into.