Just a personal opinion - I wouldn’t do a head gasket repair without getting the cylinder head surfaced. Make sure the shop knows to NOT mess with the cam side. When I take one in I always mention it.

We can't see the link here. If you have the standard cone shaped tester, you can fit it in the top of the coolant header tank.

If it is an actual pressure tester, then you need the adapter to fit where the coolant cap is. Remove the cap and then screw on the adapter in it's place.

Neil.

Did you have any software updates over the years? Maybe the feature was turned off. Does your external temp sensor for the engine work? I think the 98 has 2 front temp sensors. One for the cabin temp readout and second one for the engine. That one is tucked up under the front on the LHS of the grill...

That is strange. It would suggest from the fact it only happens when you are moving it is coming from somewhere other than the cabin as it is hard to understand what is inside that only ticks when moving. The only thing I can think if is maybe the speedometer or possibly the famous gear teeth on the...