Can anyone explain this one:

S60
2.5T AWD
Automatic
103,000 miles

Crusing at say 60 MPH and step on gas to accelerate/pass another car and the engine jumps/jerks pretty bad; if I down shift manually and step on the gas, less to no jerking; doesn't feel like slipping in the transmission or show it with an increase in RPM; no trouble codes show.

I am taking it to the shop in a few weeks for the 105K sevice (timing belt, etc) but would rather not pay for the diagnostics.

 

Sounds like the MAF sensor. try cleaning it with carb cleaner. Do not touch the metal elements inside it with a cotton bud as some people suggest just spray with carb cleaner, rinse with warm water, dry then put it back on.

Let me know if you need more of a guide.

 

I'll give it a shot here in a bit. Thanks!

 

Bought a can of Mass Air Flow Cleaner made by CRC and tried that. Took it apart, cleaned and reassembled. Actually feels better, but still jerks sometime, just not as bad/often.

 

The MAF could be buggerd. Try unplugging it and going for a drive it improves you know the MAF is shot. They cant always be recovered. Don't worry it wont harm your car driving it with the MAF unplugged. If it is the same then i would give your ETM a clean. How is your car idling.? Are the revs constant around 7 to 800 rpm or does your car fluctuate.

 

I hate to join a thread like this but I have a 2006 Volvo s60 2.5t doing the same issue no cel but normal- hard acceleration the car jerks I dont see any vaccume leaks my maf sensor looks like it's working every time I tried to replace the MAF it would throw a code for performance or something. But if I put the stock mad back in it the check engine light goes away but no matter what it jerks under acceleration. I don't completely see how a throttle body could be the reason. And replaceing the coils and fuel injectors is a little out of my budget ATM and not even sure if that could be the reason as well.

 

dunno if your year is part of the cars plagued by ETM (electronic throttle mechanism) issues. Check Xemodex or Midwest ABS about symptoms and years of cars with throttle body issues (usually worn contacts - figure $250 to have yours rebuilt).