02 XC70 shuddering at idle Topic is solved

shafe36 · Post by **shafe36** » 15 Feb 2018, 12:18

I was going to get an oil change today. That's where I was headed when I turned the car on and it was shuddering almost as bad as I was after I noticed it.

I checked the air filter before I got in, snapped it back in and turned the car on. Yesterday, it was fine. Or it wasn't bad enough for me to notice, if it wasn't fine.

It stays pretty comfortably at 1000rpm according to the Rev meter, but it seems like the rpms rise and fall, always culminating with a shudder that shakes the whole car at the peak.

I haven't found anything online that matches what my car is doing exactly. No recent repairs or shop visits other than a couple new tires in the back. I'm baffled.

I'm happy to provide as much info as I can, thanks in advance for all your guys' help

Post by **Rattnalle** » 15 Feb 2018, 12:21

The idle seems to high as well. Has it always been like that? IIRC the NAs idle at about 800 and at least the 2.5T at 650, I'm guessing the 2.4T should be about the same.

shafe36 · Post by **shafe36** » 15 Feb 2018, 12:41

Yeah, I'm pretty it's always been around 1000 from what I remember. Granted, I've only had it about a year and a half

Post by **Rattnalle** » 15 Feb 2018, 12:47

And I'm guessing it's a 2.4T since it's an -02? Never owned one of those, just test driven, so I'm not sure about the idle but it should at least be as low as the NAs which have been around 800 since the 850 for the straight 5.

shafe36 · Post by **shafe36** » 15 Feb 2018, 12:54

Yep, 2.4. Reading around, it looks like it is running high. I suppose more symptoms makes it a little easier to diagnose. I've heard a million and one different diagnoses so far

Post by **jonesg** » 16 Feb 2018, 15:10

shafe36 wrote: ↑15 Feb 2018, 12:54 Yep, 2.4. Reading around, it looks like it is running high. I suppose more symptoms makes it a little easier to diagnose. I've heard a million and one different diagnoses so far

What do the codes tell you?

Post by **abscate** » 17 Feb 2018, 05:18

Cars are way too complex to diagnose by symptom. You will typically take 2-3 hours to check subsystems for faults to find what's causing a problem. It's 2-3 hours of your time or the mechanic time, who might be a bit faster.

Here I would start with finding the vacuum diagram and removing and checking each hose for splits tears and holes.

When were the ignition parts, coils and plugs, last checked or replaced?

shafe36 · Post by **shafe36** » 20 Feb 2018, 12:04

Thanks for trying to help guys! I changed the plugs and put some fuel system cleaner in Sunday. I accidentally bumped the air filter and, lo and behold, the problem went away for a second. Looks like the MAF was bad and choking out the rest of the engine. I unplugged for a few minutes and it ran like a dream! The RPM even went down to around 800 at idle. New one is on the way! All is well. Thanks again!

Post by **Rattnalle** » 20 Feb 2018, 12:20

Nice accidental trouble shooting there

shafe36 · Post by **shafe36** » 20 Feb 2018, 12:30

Hey, I'll take it