Over the last 2 days I have been having tire pressure issues, all 4 tires have been losing pressure. I have been using a good analog pressure gauge to check the tires. Three tires are down by 3 lbs. and the drivers rear tire is down by 6 lbs. My Roadster has 6914 miles and have the Conti ASP Tires, has anyone else experience this problem? I am going to mark the pressure to night when it cools down a little and check it again in the morning. I would assume that if the tires loose anymore pressure, then there are problems with the tires/rims. My car has not hit any large potholes most of the roads that I travel on are smooth country roads. I have also considered the temperature here, over the last 2 weeks the avg. temp here has been about 94 degrees. I am planning to take it to the dealer in the morning. Just had my 7000 mile service done about a week ago and the tire pressure was dead on. If anyone has any thoughts, please chime in.

 

The heat shouldn't be the problem, basic science... when a gas heats up it expands thus your tires should be over inflated. I would expect air temp to play a role in January.
Doesn't sound like a TPMS issue as you have double checked manually with a tire gauge.
At this point it seems like a leak but all four tires? bad rubber, rims or stems.
Do you have the stock stem caps on it?

 

Stock stems and caps are on all tires and I have checked the valves for leaks. I am originally from NY and the car was purchased there. But its toward the end of summer and when winter hits the car was parked and the TMPS was always on. I also thought it was a bit strange that all 4 tires are losing pressure. I don't think that I could possibly get 4 nails in 4 separate tires, what are the odds? I guess I will have to let the dealer figure it out.

 

just to double check for slow leaks get a spray bottle and fill it with water add a little soap to it and spray the rim edges and valve stems. Get them good and soaked and look for bubbles. Don't forget the inside rims. Will be easier to take the wheels off the car to check them. If still no leaks, check all of your rubber the same way.
Still no leaks... off to the dealer.

let us know how you make out.

 

Did more research on this and if you have verified that there are no actual leaks in the tires. It sounds like the TPM module may have failed.

The Universal Garage Door Opener/Tire Pressure Monitor odule is located in the headliner near the inside rear view mirror. The Tire Pressure Monitoring (TPM) system utilizes a control module to monitor and operate the system. The control module also has a universal garage door opener integrated along with it.

The tire pressure monitoring system utilizes transmitters that are located in the valve stem of each tire to communicate the tire pressure condition to the module. If a tire has low air pressure, an indicator light on the Instrument Cluster is illuminated. The vehicle operator must check the tire pressure of each tire in order to determine which tire has a low pressure condition.

The TPM and UGDO are not serviceable and if one or the other fails the entire unit must be replaced.

 

Just had my 04 Coupe in for the TPM staying lit. They will replace my TPM module as soon as it comes in. Tech didn't find a TSB on it, but he checked everything first. My symptoms were. TPM light starting coming on and going off during my 112 mile round trip commute. Tire pressure 33/34 all around. No leaks on bead or valves. Hope this fix works.

 

FYI: The reason I asked this is because the valve stems are aluminum as are the stock valve caps. If you replace these with non stock caps that are NOT aluminum it can cause corrosion in the valve stems. Aluminum does not like to be in contact with non aluminum metals and doing so facilitates corrosion.

If you are going to use non aluminum caps you may want to wrap the valve stem threads with teflon tape (pipe tape). This will limit the contact between the two different metals. It will also seal the threads from moisture and corrosion.