I was driving around 45mph, constant speed and heard a warning beep from the dash. Looked down to see a high temperature warning. Glanced over to the temperature gauge and saw the needle moving up rather rapidly. I quickly pulled over to side and immediately cut the engine. After recovering from the thought that my less-than-a-month-old GTO had just died, I checked under the hood. Everything looked fine, so I cranked it up. The thermostat showed a normal temperature and didn't change after idling for a while. I then drove off and haven't had any problems since.

A search of the board showed that some people have experienced thermostat anomolies, but there were no descriptions of these problems or solutions given. Has anyone else experienced this? Should I take it in to the dealer or will it just end in a wild goose hunt?

Its happen to me I think three times, I think its just a bug in the computer

Happened to me once, about 3wks. after the guage gremlin attacked. Everything was fine. Thought I was DOOMED!! j/k!!

lol :D

GM is aware of this issue and has issued a technical service bulletin to fix it. I'm attaching part of it below:

Speedometer Erratic Movement, Fuel Gauge Does Not Go to Full After Filling, Engine Coolant Temperature Gauge Reads Hot and Coolant Temperature Light Illuminates (Reprogram IPC) #05-08-49-003 - (Jan 20, 2005)
Speedometer Erratic Movement, Fuel Gauge Does Not Go to Full After Filling, Engine Coolant Temperature Gauge Reads Hot and Coolant Temperature Light Illuminates (Reprogram IPC)
2004 Pontiac GTO

Built Prior to VIN Breakpoint 4L29601

Condition
Some customers may comment on one or more of the following conditions:

• Speedometer jumps erratically. Gauge may go up to 200 MPH or not return to zero.

• Fuel gauge does not move off empty when tank is full.

• Engine coolant temperature gauge reads hot and coolant temperature light illuminates.

These conditions may be intermittent.

Correction
Technicians are to reprogram the IPC with an updated software calibration. This new service calibration was released with TIS satellite data update version 1.0 available January 10, 2005. As always, make sure your Tech 2® is updated with the latest software version.

Important: Vehicles built after the VIN breakpoint must have the IPC replaced to correct these conditions.

Thanks for the TSB info. Since my VIN is 4L305819 I guess the IPC will be replaced instead of reprogrammed. Strange that a newer IPC can't be reprogrammed to fix the problem. Maybe the later builds have the updated software so the problems indicate a hardware problem.

I had a problem with my tach and speedo at the same time sitting waiting in line, I started her up and the speedo went up to like 20 while i was stopped and the tach was vibrating at about 200RPM

Shut the car off, restarted, did it again, restarted again, no problem since.

I'll chime in here as well :D :D

I've had the temp gauge hot alert once while driving as well. I about s*** my pants when it started to alert. I pulled over and as soon as I did the problem corrected itself.

I also had the speedo/fuel gauge go wacky on me as well...luckily I was just sitting behind my garage letting the motor warm up. The speedo was pegged at 200 MPH and fuel was on empty. I thought man this is strange.

I leased my GTO from Rodgers Pontiac in Dayton who subsequently sold out the franchise to Reichard Buick. I took the Goat in to the dealer(before I read this thread about the TSB) over the temp gauge issue and they told me not to worry about it as it self corrected. I believe they're(Reichard) having teething problems getting up to speed on the maintenance of the GTO's. When I had my oil changed the technician came and talked to me as it was his first chance to work on the GTO. On my next maintenance visit I will mention the TSB and hopefully they will have the program to update the computer.

Chris :D :D

So this was corrected for the 2005s right? If not is this all covered under the warranty? I'm pretty sure it is but it doesn't hurt to ask.

Yesterday just after dead cold start my temp gauge pegged & chime sounded. It then went to a normal & proper reading. Now my fuel gauge doesn't seem to move & my trip computer keeps registering the same distance to empty & I drove 80 miles in the last two days. My VIN # is just after the cut off listed. Car has about 1600 miles on it. :(

So this is different from the rubbing wire bundle problem? It does sound much easier to fix!

Most have had the problems fixed at dealers under warrenty without any further problems.

I also have had my temp gauge rise up and chime two times - and then immediately return to the "normal" reading.

However, I have noticed that when I start my car, the temp gauge will slowly work its' way up to the notch below the mid-point. That is normal enough. However, regardless of if I am sitting in traffic or cruising at highway speeds, the gauge stays in the identical position. At idle, I can feel the fan going on - but again, no movement in the gauge. Is this similar to what you all have experienced as well? It is different than what I had experienced in my Bonneville GXP or my old Grand Prix GTP so I was just curious......

Dave
04 GTO
04 Bonneville GXP