Jochen my 98 GP GT 4 door sedan I passed on to my son. It now has a little over 100,000 miles. Been a great car for us. The 3.8 is a really solid motor. The only areas I've had troubles with over the past 10 years:
Upper intake manifold crack, this shows up as a coolant leak on top of the motor. $110 for an improved Dorman upper intake manifold will solve your problem. Many of the 3.8 are prone to this.
Wiring harnesses, had multiple failures of power windows, nuetral safety switch, solenoids in auto shifter and ignition switch solenoids fail. The problem in every single case was not the solenoids or power window actuators (except for one drivers side power window actuator mechanically failed) it is the wiring harness connector block terminals. GM farmed these out to Mexico and the spring contacts in the harnesses have zero spring tension, they are highly mallable like you see in very thing soft copper and once they bend or are subjected to heat and cold they no longer make contact with the components terminals the block is connected to. I cut the terminal blocks off and soldered the wires directly to the ignition switch, window actuator, ect and in every case the failure never repeated. GM doesn't explain why they built their harnesses with defective components. The Gm dealer and techs keep wanting to sell me hundreds of dollars worth of electronic components when there is nothing wrong with them because they all say they've never heard of this. I think they just want to take my $$$. They've got to know there is a problem with the wire harnesses in these vehicles.
The tailpipe exhaust hangers stretch and you'll need to replace them, very easy and inexpensive, they are rubber and they stretch.
Radiator had to be flushed every two years until I got rid of the Dexcool coolant and went back to Prestone green. The Dexcool turns to sludge very quickly in this car for some reason. But not my 04 GTO, can't explain it.
As I mentioned did have a drivers side power window actuator fail. The plastic parts simply broke and failed. The bracket is made in Korea, the motor in China and the wiring harness in Mexico. American car right?
Headlight switch failed a year ago, simple fix to replace it.
No problems with the heads up display and I'd recommend it.
Been a good car for us. The wiring harness issues are my only concern with these cars.
