My car thinks she's a kangaroo..
 

Did a pleasant 50km run into a nearby country area today, quite hilly so I was really enjoying some switch-back roads, little other traffic around.

Coming out of one steep descent, which resulted in a mildly stomach unsettling "bottoming", I hit the next incline at full force. Then the kangaroo lurching started, rev counter swinging wildly back and forth between 500-2000 revs, loss of power and a very unhappy sounding engine. After stopping she idled fine, but wouldn't respond under load. I'd been running on the right tank so, still idling, I switched to the left and very cautiously resumed driving up the hill. Still missed badly for about 30secs, then suddenly it cleared and the last 20kms home was a perfect run.

My thoughts: Contaminated fuel (dirt or water) in the right tank, perhaps sloshed around due to my spirited road acrobatics and pushed into the lines. Over the next day or so I'll drain the offending tank (about 1/3rd full), partially refill with fresh fuel and drain again, then finally fill the tank. I'll replace the filter while I'm at it. I regularly alternate between tanks to keep everything exercised, but the car had been sitting unused for 2 weeks with both tanks approx half full.

Any other thoughts, as always, will be very welcome :icon_shrug:

I think you just scared it.

You cant get too much air in a 2 tonne car Tony, you really should leave that to the WRC guys :-) I will be interesting to see if you find anything in the filter.

Wasn't going hard enough to get airborne, but it was a very short pit at the bottom of the hill before next ascent. As for Subies Steve, they're the pesky little critters we pick out of the grill after a run aren't they?

RH tank not venting properly???.

"Pop" the flip top fillers, go and do it again, and see what happens.

I would be checking for crud in those 1/2" supply hoses and valves to the pump.

It has the symptoms of pump supply fuel starvation.

Steve, I misread WRC as WRX, hence the Subie reference!

Maybe I should forget any ideas about entering at Winton :P

How does the venting route Grant? Is this the system with the valve that people sometimes doctor at the charcoal canister, or is that a different vent?

Never got intimate with a S3.

Same year XJ-S has that "type" of system, and since we are in OZ, simply vent the tanks to atmosphere. That I did with all my S2's.

Drill a 1/64" hole in the alloy tank topper just alongside the flip top catch thingy. All done. Leave all the other rubbish as is just coz its easier than removing it.

Thanks Grant. So this bypasses the system reverting to old school - a nice easy fix! Just to be sure I'm understanding this, do you mean the hole is going into the alloy base, or the hinged lid/catch part?

The alloy bit.

I drill just near the "catch" bit for the shiny cap hook. Open the cap, look at the filler spout, and simply decide where you want to drill that hole.

Stuff a rag down that filler, drill the hole, then pull the rag and the swarf out in one sweeping movement.

Aussie knowhow, cant beat it.

Now you will need to keep those drain tubes CLEAN, so the rain does not fill that area. I have NEVER had issues with that however. That hole is so small anyway.

PROTECT the paint with cardboard or similar, coz that chuck teething on the drill will do very obscene things to your paint.

Drop into Bunnings etc and get a few spare drill bits, ya gonna break a few.

Got it mate, thanks. May have been a dumb question but it comes under the "measure twice - cut once" category i.e. if you ain't sure, check :)

Just to finish off the tale...

I decided to begin with the lowest-tech approach I could think of: Do nothing except flip the caps as suggested by Grant. See if she does it again.

She hasn't missed a beat since, including a 400km country trip through hilly country at some pretty high speeds.

I didn't even drill the vent holes, and the filter is fairly new anyway.

The "hiccup" could have been caused by one of a number of possibilities but the symptom hasn't reappeared at this point, so my conclusion on these things is see if it happens twice - if it doesn't, leave it alone! Or at the very least cover off the simple stuff before diving in.

Well done.

Look at the drinking time you just created.

Indeed. Funny though, for some reason my other half didn't think to offer the same suggestion...:icon_beerchug: