zsherf

So I've had a slightly rough idle on my 2010 Panamera 4s since my ownership.

87K Miles and in the past 12 months have driven 10k and have had the following work completed by The Porsche Specialist in Broomall PA:

Control Arms, upper and lower at indy

Motor Mounts at Indy
Fuel System Cleaning at indy
Coils and Plugs from FCP euro, DIY
Throttle Body Cleaned at Indy

The main issue is that when I accelerate, there is a lull in power from 2800-3200 rpm, before and after that its fine and most noticeable in 3-4th gear. Its not always present but it is a majority of the time.

One thing that I have noticed is that if i go light throttle through that range it seems to actually pick up power and surge there.

Any thoughts are super helpful!

Shrike071

What was involved in the "fuel system cleaning"? Fuel filter replacement? Getting more power at lighter throttle sounds like a fueling problem. Either a plugged up filter or tired fuel pumps. If you're mechanically inclined, you can test the fuel pressure yourself which would tell you if the system is working correctly. In my hot rod, I just tape the gauge to the windshield and go for a drive while watching the pressures. Could also be a dead spot in the TPS. Do you have any way to datalog the car?

zsherf

Thanks! This is a good thought and I was leaning towards fuel system as well. However the panamera is DFI and not sure if the fuel pump can be monitored easily mechanically.

Shrike071

There is actually a process to measure PSI, but to do it properly takes both the PIWIS as well as some special gauges. The high pressure is measured via PIWIS and the low is measured via the gauges.

You could kind of go around the actual measurement by using some datalogging software. If you have a device capable of logging, watch your O2's and fuel trims around the RPM's when it bogs out. If it's fuel, they will probably show a lean spike evidenced by rapidly increasing trims (the car wants to add a ton of fuel). If it is an ignition issue, you'd see the opposite - a rich spike - and the car would show negative trims because its pulling fuel. I think even the POR2 can read O2 data and fuel trims, so there are some relatively cheap options out there that can do this.

Shrike071

I wanted to add that an air/vacuum leak would show as a lean spike on the O2's, too. The car would interpret the extra unmetered air as a lean condition on the O2s and dump in fuel to try to get it to where it wants to be. The trims would all be positive. Most of the time, a vac leak shows up first as a hunting idle, and is apparent throughout the RPM range. I say "most" because my car had an intake manifold leak that would self-seal at low vacuum and then leak at higher vacuum levels (like at idle..). At WOT, the car was a beast. Driving it around town it was terrible. Took me a long time to figure that one out.