Ive run into this problem myself. First thing you need to do - Go to supercheap and get a can of aerostart or start-ya-bastard.
What your doing is looking for vaccum leaks. WIth the engine at idle (max vacuum) carefully spray around these components, listening to hear if the engine revs up. Be careful, this stuff is flammable, and contains a high percentage of ether. Only need to spray a little bit.
Spray -
Seal between upper and lower intake manifold.
Seal around top of plenum.
Seal around IAC and Throttle position sensor
Back of plenum where vac hoses attach.
Back of left rear head where the vacuum distribution block sits.
Brake booster especially where the vac lines attach.
Vac hose under the throttle body - one goes to front right of intake manifold, the other goes to the back left head to the vac distribution block.
Joins between Throttle body and maf hoseing, and maf hoseing and maf.
No Rev ups ? Ok step 2.
pull all the spark plugs. Play close attention to the plug that comes out of #6 (closest to driver) if that plug is heavily oiled, replace the PCV.
Look for signs of lean burning - a whitish residue, powdery. Lean suggests blockage in fuel systems, though it is NOT definitive.
Replace plugs if necessary.
Remove and inspect plug leads, looking for signs of arcing. The rubber will burn under arcs, leavving a bluey ehite powder on the heat shields. Replace if any doubt.
At this point, replace the Coolant temperature sensor. It sits under the thermostat housing in the gooseneck at the top front of the block. It's cheap, $25 and can the source of a few hard to diagnosis problems.
Inspect your Coil packs. Look for cracking or heat ageing. replace if in any doubt. These are not so cheap. When a coil pack goes, they can often take the DFI out that they sit on. This unit basically triggers the coilpack to discharge, providing spark to the cylinders. If you lift of the coil packs, you may see heat ageing or discolorouration on the DFI contact plate. If you do, replace it. Burtons will sell you a set of coils and a DFI for $300.00
Still no resolution ?
next thing on the list is the cam angle sensor and the fuel systeem. The CAS has input on when the Coils fire, so your 'timing' can drift if it misbehaves. On the fuel side, check and replace your fuel filter, Clean the injectors (drop them off and check that the baskets in the end arent full of crap, and that all the seals are intact, rinse them in clean fuel, then rinse them in method and let dry. be sure to use re-assembly lube on the seals when re-assembling, stuffing these seals is a sure vacuum problem.), and also replace the fuel pressure regulator while the plenums off. It sits on the end of the fuel rail, and the regulator is held in by an internal circlip, on the broad face.
Next on the list is the complex stuff. The PCM - $88 from a wrcker - VT2 is only compatible with VT2 with same gearbox. With the pCM out (the passenger footwell) ensure that you don't have a water leak from the windscreen - dirt trails will be evident. The PCM will need a Tech with an OGBD scan tool to make the PCM talk to the BCM. it wont run without it.
Still no worky ? Welcome to my world.
This is exactly the same series of events i got with My VT2 and I've got to the point where it very very rarely hesitates, and only stalls because i have deliberatley retarded timing at idle (oversize Throttlebody gives big torque response when cracking the throttle).
Good luck - and if you find something that works please let me know.
Cheers
