Rather than continuing to replace expensive bits and pieces that aren’t – so far – curing the problem, have the vehicle electronically scanned to see what fault codes are being logged by the on-board computer.

If you’ve completely replaced the ignition system, then you might need to start looking at the fuel system. The V6 engine was a direct-injection unit which means it can start to be affected by a build-up of carbon in the intake system. That alone could be enough to cause your problem.

But don’t rule out a dud injector or failing fuel pump, either, as both these things can an allow the engine to idle properly, but develop a case of the staggers when you put the engine under load. Even a dirty fuel filter can cause this sort of mayhem, but until you interrogate the computer, you’re flying blind.

You have two issues here. The first is the transmission problem, and, to be honest, on a late model car like this, an automatic transmission specialist is where you need to go. A slipping transmission can be caused by all manner of things, starting with the simple low fluid level, to the catastrophic mechanical failure. In between there are also electronic possibilities to be investigated.

Your second problem is that you’ve spent otherwise useful money on an aftermarket extended warranty. All too often, these warranties are carefully worded to exclude a range of possible problems you might experience. You might be lucky and the warranty will cover the repairs (it’s definitely worth a try) but don’t be surprised if the fine-print scuppers any chance of the warranty paying out.

Unfortunately, the odds are against this problem being a simple blown fuse. This series of cars is notorious for ABS faults and the cause is almost always the control module that has failed. A replacement module is the only real fix.

You can either source a brand new module, a reconditioned one or, for about $100 or so, a second-hand module from a parts recycler that specialises in this type of vehicle. The market for these is well served purely because failures of this component are so common.