brief hesitation at highway speed

hu5ker555 · Post by **hu5ker555** » 03 Aug 2021, 06:44

2008 S60 2.5T 202k miles

I've had this vehicle for about 10 years now. The car runs and idles like new. Only issue is a brief hesitation/stumble that occurs at highway speeds. I'm typically cruising at 50-60 mph, and when I go to accelerate, there is some hesitation/stumble that happens for about 2 seconds, then it goes away and the car accelerates and runs fine. There are no CEL codes. It's been doing this for the past year or two.

I just replaced the fuel filter, but no luck. Can't imagine that it would be the coil packs/plugs because I would expect to see a CEL code for that.

Any ideas/suggestions?

Post by **jonesg** » 03 Aug 2021, 17:07

hu5ker555 wrote: ↑03 Aug 2021, 06:44 2008 S60 2.5T 202k miles

I've had this vehicle for about 10 years now. The car runs and idles like new. Only issue is a brief hesitation/stumble that occurs at highway speeds. I'm typically cruising at 50-60 mph, and when I go to accelerate, there is some hesitation/stumble that happens for about 2 seconds, then it goes away and the car accelerates and runs fine. There are no CEL codes. It's been doing this for the past year or two.

I just replaced the fuel filter, but no luck. Can't imagine that it would be the coil packs/plugs because I would expect to see a CEL code for that.

Any ideas/suggestions?

VIDA might pick something up in flight test mode, I would look at the throttle body first.
VIDA shows CVVT response time....although that usually sets a code.

Post by **abscate** » 03 Aug 2021, 17:44

hu5ker555 wrote: ↑03 Aug 2021, 06:44 2008 S60 2.5T 202k miles

I've had this vehicle for about 10 years now. The car runs and idles like new. Only issue is a brief hesitation/stumble that occurs at highway speeds. I'm typically cruising at 50-60 mph, and when I go to accelerate, there is some hesitation/stumble that happens for about 2 seconds, then it goes away and the car accelerates and runs fine. There are no CEL codes. It's been doing this for the past year or two.

I just replaced the fuel filter, but no luck. Can't imagine that it would be the coil packs/plugs because I would expect to see a CEL code for that.

Any ideas/suggestions?

PEM is a possible. Drive it a bit to see if a code sets, though

hu5ker555 · Post by **hu5ker555** » 03 Aug 2021, 18:04

Any chance this could be a TCV problem?
I've seen that IPD Heavy Duty TCV also supposedly improves turbo response and performance, better than OEM so that's interesting.

Only other thing I can think of is maybe the fuel pressure sensor.

Post by **cn90** » 03 Aug 2021, 19:45

Get a spare PEM at junk yard (or ebay for $40).
Swap and see what happens.

blanketbum · Post by **blanketbum** » 04 Aug 2021, 10:08

I've been having this same issue for the past week. I thought the same thing about not throwing a CEL, especially since it's thrown them even when I didn't notice any hesitation.

To fix my issue I ordered a single ignition coil only cost me $30 from Amazon. (Delphi GN10331) I swapped it through all cylinders until I noticed the problem go away, burned my hands a few times removing them, don't recommend.. And ofc cylinder 5 was the issue.

Previously I changed my plugs and injectors, and a single ignition coil. Next up I'm replacing the other 3 ignition coils because the majority of mine are mismatched and it bothers the hell out of me.

Also, many people will say only replace them with the $80 OEM Bosch coils. Personally I didn't think there would be an issue swapping an aftermarket one in, however I swapped the one above in because I couldn't find anything but positive reviews on them. Also note that sometimes the rubber boot is a bit shorter, I think this is a redesign, as long as the spring is the same length.

Best of luck!

Post by **abscate** » 04 Aug 2021, 10:18

This is where VIDA shines as it logs misfires before they occur enough to set the P0305 code, in this case

hu5ker555 · Post by **hu5ker555** » 09 Aug 2021, 12:48

So I ordered a new fuel pressure sensor. We'll try that first.
If that doesn't work, next try will be grabbing a PEM from the junkyard and swapping it out.

Post by **RickHaleParker** » 10 Aug 2021, 14:41

Fuel Injectors and O2 Sensors can cause performance issues without lighting up the CEL. In some cases without triggering a DTC.

How many miles on the clock?
Are the Injectors and O2 Sensors original factory install?

Scan results from VIDA would be real helpful. Highly Probable: more cost and time effective then throwing parts and money at it.

hu5ker555 · Post by **hu5ker555** » 11 Aug 2021, 17:40

Well, I tried replacing the fuel pressure sensor. No change.
Ordered a new TCV (Pierburg). Should arrive next week.
Might make a run to the junkyard this weekend to search for a PEM.

It just seems like the turbo wants to kick in but does not. Car runs and idles great, and no codes... just no boost.