Hi All,
I have an issue and will call it "throttle response" right now but pretty sure this is just the symptom of something else that seems to happening and looking to see if the community has any experience on what I could do, to isolate the problem.
Sometimes, the car drives like its detuned or restricted. It still revs to the top but in a way that's much slower & rougher, takes it time. Definite change in how the car responds to the throttle, like the response is numb, you have to step on the accelerator much further but don't get much urgency back for it.
There's an audible difference in engine harmonics too. The tone of the rumble sounds much flatter and almost like a rough diesel engine
Most of the time, it feels sublime - revs sweet, smooth and very urgent. You can feel every millimeter of the accelerator making the car get that much angrier, it's awesome!
Car stats:
987.1
Cayman S
, 85k kms. Probably has had a hard life.
Standard engine (no mods that I know of) though an independent specialist did say that my
battery
wasn't exactly the right type and they reckon there could be weird things from this
Hard rubber mounts + Function 1 engine mount insert (this issue had appeared before this change)
There are chassis mods like PSS9's LCA's etc.
At the moment, I'm still trying to find way to identify the trigger or conditions but it seems to happen randomly.
Things I am trying,I thought the trigger was how I started the car. I usually let it check the oil, so I tried just inserting & turning key asap.
- 8/10 times it seems to run perfect
- I think it tends to happen after the 3 or 4 start up, after having been driven around but again, not consistent yet.
Thinking it could be to do with heat but the car can run perfect on a warm summers day and issue can occur on a very cool night.
I continue to speculate something to do with airflow but researching around, there's so many plausible problems like sensors, clutch delay, cats,
DME
retarding, bad fuel, detonation etc
Your thoughts would be appreciated!
I would start off by removing and cleaing the
MAF sensor
.
I would second this suggestion.
I experienced similar symptoms (much worse actually) in a 996 a few years ago.
After searching through some forums I learned that such rough sluggish running could be due to a dirty MAF or dirty throttle body.
In a 996 both are easy to get to, perhaps a bit harder in a 987 due to engine location.
I removed and cleaned both, with cleaner specifically made for each, and had no further problems afterwards.
So, it was either a dirty MAF or a dirty throttle body (or both, I suppose).
second the idea of MAF & TB. how is your air filter & intake or the vacuum hoses?
Circling back on this thread. I eventually replaced the MAF etc but the car would still intermittently feel like it was detuned.
I was prepared to replace the O2's when the
AOS
eventually failed. After replacing the
AOS
, the throttle response is now back to consistent feel and the torque feels proper right throughout the rev range.
Thinking back, there was one symptom that could have indicated that
AOS
was having an issue - removing the oil
cap
and gauging the suction. I remember that it was quite hard to get the
cap
off so this could have indicated that the
AOS
was on it's way out. If it's sucking quite heavily, it could be a problem in the
AOS
creating low pressure.
Interestingly, over the last 2-3 years, I haven't had any of the classic
AOS
symptoms. No smoke on start up or consistent oil consumption. Occasionally, I would have the need to top up oil (like once in 6 months) which I thought was pretty normal. Sometimes there was smoke when hitting 7000+ RPM.
It's actually a cheap item to replace so would recommend proactive replacement, especially as oil ingestion occurs when it does fail, impacting the MAF, sparks and O2's. if too much oil get's in so it can be a bigger mess to clean up
