I've got an 08 Type S w/ 107k miles 6MT. I know its time for the big service, but i've been getting a pretty bad misfire/stutter below 3k RPM, it wasn't that noticeable at first..but it seems to be getting worse with time. I'm going to start with plugs and basic tune up items first, but I just have a feeling this problem is more complicated than just plugs. Someone suggested maybe a valve adjustment..but iI wanted to know the symptoms of that and find out how I know if i really need it or not. Also whats the average price to have shop do that?

 

285 at a well priced independent shop, I had mine done a few months ago and the timing belt service was a different charge/service. Makes the car run much smoother

 

What mileage did you do yours at?

 

105 haha. Now at 107

 

I couldn't tell any difference after a valve adjustment at 107K. Nada. I'd be very surprised if valve clearance is causing your problem. I also kind of doubt it's the plugs. These iridiums are still good even at 105K, but you should consider replacing them.

Did you get your codes read? I'd be a bit concerned that maybe the tensioner is weak causing the belt to slip a tooth or two, but if the engine runs fine at 3K rpm or higher, I doubt that is the issue. Get the codes read and post back here.

 

No codes unfortunately. I do get the occasional fuel cap message though, so I know I need an evap valve, but that wouldn't cause my problem would it?

 

labor for valve adjustment is about 2 hours for an experienced tech, 3 for not so much.

I'd highly recommend you get new valve cover gaskets when you do the valve adjustment. Check your spark plugs to see if any oil is on them. If yes, you probably have a bad spark plug tube seal that's on the valve cover.

Oil level is good? Check the intake boot (the ribbed one connecting to air filter) to see if it's cracked. They tend to crack and let unmetered air in causing all sorts of running issues.

 

Plugged EGR valve? Take it out and shake it/blow compressed air into it.

 

You think it could be that?

 

I checked the boot and couldn't find any cracks. But I'll check the plugs too. I hate misfires without codes!!

 

So I've been experencing something like you are describing. I have a 08 type-s 6MT with 107k lol. So do you feel it more at a certain rev bands,? Mine is most noticeable on a cold start, but once it warms up and drops under 900rpm it runs smooth. I can still feel a slight shutter when warmed up when reving up to 3k as well (only in netruel).

Things i`ve done to try to remedy, all made no difference:
1. Changed spark plugs - oem
2. Changed water pump, belt, tensioner, idler. -oem
3. EGR valve replaced - not oem
4. Vacuum tested, no air leaks
5. Throttle body cleaned
6. PVC valve replaced - oem
7. Replaced MAF sensor -oem

Check your short and long fuel trim, is it high?

Once under load i cant feel any type of shutter which is why im not really worrying about it.

 

I get this shudder too and i read somewhere it could be the flywheel. Hasn't caused a problem in years.

 

The difference is mine shudders under load..idle is pretty smooth for the most part. Its just 2.5k-3k rpm band thats really sluggish.

How do I check fuel trims?

 

Torque Pro

 

Sounds like a similar issue I had with mine although it's a 3.2 not a 3.5. Under 3k rpm it just feels like a dog, very sluggish which had gotten worse over time. Changing spark plugs didn't help much but after doing the valve adjustment I noticed a big improvement. Throttle response was much better especially under 3k rpm. Give it a shot if doing the other things others have mentioned doesn't help.

 

Yeah i think i'll call around to some local shops and get a few estimates on that.

 

I second the EGR valve. I had a slight skip that turned into a full on random misfire in my CL. Just had 105k service done. Tried to clean it up, but wound up replacing it and it hasn't been back since. Try unplugging it and see if it goes away. You check engine light will come on but it shouldn't skip if that is it.