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About Mongoman

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  • From
    Los Angeles, CA
  • Porsche Club
  • Present cars
    05 Cayenne S
  1. OK, here's the rundown: The idle RPM stumble issue still isn't fixed - bad as ever. The explanation that we have come up with: Engine is fine. Transmission is fine. Driveshaft is semi-fine. But: The combination of engine mounts AND drive shaft may cause my issues. When I take my foot off the gas, the engine goes from load mode into follow mode - causing the engine to 'wiggle' a little in the engine mounts. That wiggle then translates onto the driveshaft, which, in turn, also wiggles a little. By the time both wiggling has caught up with the new load circumstances, it comes as a jolt on the
  2. Sad, sad update. I'm sitting here with a new invoice on my desk - $1407 to have all 8 coils replaced by my local Porsche dealer. I could've changed them myself for less than $400, but I figured if they finally found the issue - let them have the business. Remember, by now I'm almost $7k into fixing a simple idle stumble issue!!! WTF??? As I went to pick up the P!G today, even as the car was handed over to me, it was still idling rough!!! How phucking arrogant is that? Charging me $1400 and then handing me over the defective car, probably hoping I won't notice? I'm done with this. I left th
  3. Good idea - I have checked the fuse for the #2 bank, which is fuse 8 in the engine fuse box compartment - for loose or corroded contacts. Everything seemed very clear, the contacts were tight, no corrosion - I replaced both the #7 and #8 fuse, just to be on the safe side. That really leaves me down to a fuel line problem, a camshaft position sensor problem - but as the problem occurred ONCE for a matter of seconds over the last 5.000 miles, testing WILL be difficult. I may just have to wait until a completely failed CPS leaves me and the pig stranded on a steep mountain road, past midnight,
  4. Thank - really good step-by-step guide - yet, I think, the reason we haven't been able to put our fingers on it. In the P0300 code workup, the diagnostics stop at step 12 - as the suggestion is to proceed to step 12, effectively looping itself back to 12 gain. Does not make sense! But I guess the answer to my problem is: It was an intermittent problem, and until it rears it's ugly head again - no way of finding out what it was. Again, I'm very shocked at Porsche quality with apparently numerous single points of failure that not only leave you with a rough idle or a check engine light - but s
  5. We checked it today with ye olde Bosch KTS650 - P300, P305, 306, 307, 308 - all at the same time, starting with 800 RPM. Position sensors checked out fine, too. Oxygen Sensors fine. But: Everything else is fine, and the codes are gone. In short: I still don't know what was going on. I don't think it would be the coils as we changed all 8 of them to the latest '9' series, plus there is no way on earth ALL four coils on bank #2 would fail at the very same second? Am I wrong? Our best guess would be either some weird ground issue on bank 2 or something with the camshaft position sensor;
  6. I did. P300 and P305-P308 were the only codes stored. No further codes. This thing really drives me insane...
  7. OK, this just keeps getting better. After having very odd rpm spooldown roughness issues that remain unaddressed, the car jerked on me shortly after a cold start like never before - even with the flashing CEL - that went away shortly after. The codes were P300; P305, P306, P307, and P308. Now, all codes were clear before, and we only recently replaced all plugs and coils. What's odd here is: 1) CEL went away after a few seconds 2) idle RPM went up the high 800s after this episode 3) ALL misfires occured simultaenously on the same bank, leading me to think it can't be the coils or plugs.
  8. OK, A little update on my issues: Changed both fuel pumps - IDLE DIP ISSUE GONE!!! :-)) All the other issues, most remarkably the stumbling as RPM spools down - are still there :-( Azelaya, good thought on the vacuum leaks - even though someone apparently checked for leaks, it sounds like it would make sense to change the tubes - what symptoms were you having before you changed your tubes? The stumbling or the idle dip? The trottle body would have been my first guess, so we cleaned that early on and reset the adaption twice. There are still no error codes. Before I get one of those new valv
  9. We did clean the throttle body; didn't change anything. We didn't think that the torque converter seal would be causing my issues; but along the way, we found that it was leaking. We simply changed the torque converter seal because it was leaking ATF fluid. I still don't know whether it's the engine or the transmission causing the stumbling as RPM spools down. The reason I'm thinking more tranny than engine is that this stumbling doesn't happen on braking. It mainly happens uphill. I think to the engine, it should make no difference is load results from driving uphill or applying the brake
  10. OK, before I get started on this on the coming weekend, I'd like to share... This is what Porsche claims: Did you know that over 70% of all Porsche vehicles ever built are still on the road? They want to drive home a point for durability. If you look through the scheduled maintenance, there are items that are due every (!) 140.000 miles or every 12 years. So, here I am, with my hardly 7 year old Cayenne - not even having hit the 140k mile mark - and I refuse to succumb to the notion that I should have to live with certain issues because I'm driving an old car. Heck, there are 80's Carrer
  11. I have all four tires the same size - and, wouldnt PSM activity cause some light to illuminate? No illumination going on here. But a fresh thought.
  12. Well I guess all the above may hold true - and I may have a combination of issues going on here: 1) the idle dip - probably fuel pumps 2) the stumbling when I ease my foot off the pedal at very slow speeds uphill - probably valve body (or also fuel pumps)? 3) the clunking or play in the tranny - probably something engine mount- or torque-arm related. There is one last thing that I can't put my finger on. Again, this only happens when slowly inching forward from a standstill uphill, and only when you just inch forward without even gaining speed. Thats when it feels like the transmission
  13. About the torque arm mounts and transmission rubber mounts: I honestly have no idea; I can go check on it. If this was indeed done, it was hidden somewhere deep within the overpriced bills that I already had to gulp.... I'll check and get back. I would love this car to just ride smoothly again; it's just sad to see a car in perfect condition, with some issues that you just can't seem to be able to fix. If I have learned anything on these boards, it's that when you think you need a new engine or transmission, chances are it's an easy DIY fix - if you know what you're doing!! Especially about
  14. OK, So let's give this a try then... I would be really excited to finally be able to put an end to these rumbling, stumbling and dipping issues. It feel's like I'm driving a friggin' 74 chevy.
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