mongo747

I have a 2011 Panamera 4, just changed plugs and coils, running much better (but it was running like crap before). Car has 79K, was not well maintained, pretty sure I did the 30K/60K service at the same time.

The Issue

From a stop, low rpm power is low, then surges around 2-3K rpm. I also have what sounds like a vacuum leak on driver side under load, but can't trace it down. At 2-3K + the car is a rocket ship, but that low rpm is like lame mode.

Some Facts

The idle is pretty steady at 600 rpms
Tightened up the air box, no leaks from there
Removed air intake completely same issue
Under load, you can hear what seems to be a vacuum leak. Took it to the dealer, and they couldn't tell
Car also has a noticeable vibration at low rpms
Car was not well maintained, has 79K miles, Porsche service has never seen the car
Just changed plugs and coils (pretty sure they are original, old rev number on coils), and oil change
Car runs way better above 2-3K
Looks like oil leak from behind vibration damper
Pulled the battery for a couple of minutes to try a ECU reset on states (don't think that's the procedure), didn't help
I can take off the oil fill cap while it is running
I do not hear any humming or noises from gas cap
Car I think hit a curb or took a dive at some point, driver side, I took car of the structural damage, but am thinking the vibration damper might have got tweaked
AOS hose to intake had some oil in it
When I hit the throttle, there is a huge air intake suck noise

Questions
There are a lot of hoses on the driver side and a lot of them that go behind the engine, are there any usual suspects for leaks on the driver side?
Is the big air suck normal on these cars when you hit the throttle?
Was thinking it might be an exhaust leak, but seems pretty impossible to even check, how do you get to the exhaust header?
Does the Panamera have a MAF sensor? If so, where is it?

Next Steps
I have a local company that does balancing, so going to see if they can check out the vibration damper. It's either that or the engine mounts which I really don't want to have to do.

Any help would be great, dealer was absolutely useless, they had the car for a month, and came up with changing trans mount, which I knew better, dropped a 1k, but at least got to drive a 18 panny loaner for a month.

I'm returning my truck lease in a couple of weeks, so this has to be my daily driver, it runs, it get's around, but her inner beauty is being covered up.

mongo747

Update
Took off throttle body, cleaned it up. Had a 1/2mm guck line top and bottom. OBD tool said TP % was 20ish, after cleaning, went to around 12. I'm thinking guck, offset throttle position.
Low rpm is way better, did adaption process.

So getting closer. Still have quite a vibration through car at low rpms in park and during driving. Took belt off, ran car, vibration went away. Put belt back on, and vibration was back.
Belt tensioner seems tight enough (haven't checked torque spec yet). Belt tensioner is bobbing back and forth a lot, its a brand new belt.

Not sure if belt tensioner is bad or not. Vibration damper seems pretty even, I've worked on lathes, so you can somewhat tell if things are off. At higher rpms, engine runs great, would think vibration damper would get worse at higher rpms.

Anybody have any suggestions on how to tell if belt tensioner is going bad?

justabout

justabout

mongo747

Paul Rathjen

Air / Oil separator? Check for major vacuum when removing the oil cap while running. Some people have complained about sucking noises when the diaphragm goes bad, as well as some surging I believe - do a search.

mongo747

jjrho

Did u check your motor mounts ?? Belt tensioner is oil filled...goes bad too...

Dartmouth

My 2010 P O S Panamera S has the same problems. Vibration, low idle rpm, runs rough. 2 dealerships don't know what is wrong. Replaced everything that it may have needed. Plugs, Coil,hoses for slight leak antifreeze, PDK service, 2 solenoids for lifters. Check engine light on. Vibration and low rpm is my main concern. This P O S is costing me a fortune and it's running like crap. PDK is clunky. I have a 09 997.2 that has PDK and runs like a clock. This PDK in the Panamera is clunky. I hate it right now. Starting to think of dumping it and taking a loss. It's going back to Porsche dealership one more time. I have no faith they will fix it.

mongo747

Dealers are not interested in fixing these challenged cars, they want to charge 800 bucks for changing air filter. If we were in Germany, I'm sure it would be a different story. Cleaning my throttle body helped a ton for low rpm rough, and I still need it recalibrated, which dealer wanted to charge 800 bucks for.

I used a durametric, and had a code for low fluid in trans, but not sure I can trust it. Asked deal to check it, and got a yeah sure its ok. The procedure to check is very specific, and very temperature sensitive. I am going to check the level based on ZF's procedure. Would be much easier if it was warmer and I had a lift.

how many miles on your Panny? I have 80K, so hoping a level issue, or engine mount issue, mine was in a accident.

I also got some canbus errors, wondering if wiring harness can be damaged.

Another thing I found was a bad brake switch can really cause problems, its the grandma isn't sure what peddle to hit, so it messes with the throttle so granny doesn't drive panny into a lake.

Dartmouth

I can't accept that a 2010 Panamera S with just 63k miles, that looks great on the outside and inside, has an engine and transmission that runs like a 65 Plymouth. Actually a car like a Plymouth boat will ride smoother and quieter. Codes are not the answer to problems. Logic is like you said. Check the brakes, brake sensors, motor mounts, PDK if it needs the software refreshed, check the belt idler and the throttle body. But my gut is use every certified mechanic at Porsche to put their experience and heads together to figure out what is making the car ride like crap. Is it any of these things or something else ie tires, alighnment, wheel balance. Just keep the damn car till you figure it out. Or tell me there is no fix.

gregf

I've had my 2015 GTS for a week. Not as bad as you've described, but when starting from dead stop - such as pulling out into traffic -- I get a lag with very little power, then it kicks in like a racehorse. I'd have to look at the RPMs (certainly not 3K), but I find it a very unstable situation instead of having smooth power and acceleration at lower revs. Anyone else experience this in a newer model, particularly a GTS?

Dartmouth

Porsche dealership found that the engine had major warranty work done to it before I bought it. They also found the the piston cylinder was scored and didn't recommnend fixing it. Just drive it and if the engine light comes on (again) bring it in, turn off the check engine light, then go trade it in somewhere for another car. I took their advise and traded it in on .....you guessed it...another Panamera. But this one is perfect! 2010 with only 23K miles. A real find. And affordable at $31K. Smells new, rides beautifully, no issues externally or internally.

Paul Rathjen

Glad you got it worked out.....sort of.

mongo747

No offense Dartmouth didn't work out anything, just added another troubled Panamera to the pile. Smart man.

I the OP, am still having issues, but I think I'm getting closer.

So I have changed the AOS and vacuum pump, dealing with P0455, and changed the belt tensioner. So with the A/C off, it runs and vibrates, let's say, ok. I could live with it. Put the A/C on and its starts shaking the whole car.
@justabout You mentioned that about turning the a/c on and off could affect it. Compressor works, are you suggesting it could go bad?