April 12, 2007
Q. My 2005 Lexus LS 430 is a great car but has an annoying problem. The low tire pressure warning keeps coming on. I have had the dealer take a look, they checked the tire pressure then reset the system. Do you know a way to find out which wheel is setting off the warning or a way to fix for it?
A. Your car uses what is called an indirect monitoring system. This type of system uses a mathematical algorithm in conjunction with the anti-lock brake system computer to determine if tire pressures are low. The problem with this system is it can’t determine which tire is low, only that at least one tire is low. Tire pressure warning systems are designed to illuminate the warning light when tire pressures are only just a few pounds less than the correct specification. The warning light can also come on if tire tread is different from one tire to another, the vehicle is overloaded or the outside temperature is less than 32 degrees. If you check the tires and the pressure is at the specification, turn the ignition switch to the on position and press and hold the tire pressure warning reset button. This should cancel the light.
Q. I have a 1999 Nissan Sentra with 23,000 miles on it. The horn was sounding when taking a tight turn, or would continue sounding when the alarm was set. My mechanic replaced the clock spring and the problem went away for two weeks after which it reoccurred. I took it to another mechanic who said it was a failed clock spring and he replaced it and no problem for two days and then it started again. I took it to a third mechanic and he said it is the clock spring. I can see the first one failing but not all three unless there is something that is making the clock spring fail. Is this possible to have three clock springs fail in short order? Is there something additional that the mechanics should be looking for?
A. There is a technical service bulletin that describes this problem. There are small springs that are more than likely losing there position between the horn plates. The bulletin is number NTB99-050A and the repair involves replacing the horn springs and insulators.
Q. I was very lucky to find this vehicle at the price that I did in the condition that it is in, so I really don’t want to jinx my luck. My concern is there is wear on the outside of the front tires and it pulls to the right and shakes and shimmies when turning right. Could you tell me what that might be wrong and about how much it would cost?
A. You need to start with a thorough inspection of the suspension and steering system. A badly worn wheel bearing, worn ball joint or worn tire could be the cause. You should have this looked at as soon as possible since this is a potential safety issue.
Q. I have a 2005 PT Cruiser Turbo automatic and the dealer quoted a price of $599.00 for a tune-up. When I asked why so much for a four-cylinder car the service person could not answer me. Am I wrong to think this quote is very high?
A. I agree the price seems a bit high for basic maintenance. Ask the dealer to explain what is included in the $599.00 price and compare those suggested repairs to what is recommend in the vehicles owner’s manual. The dealer may be adding in some other repairs that may not be necessary at this time.
Q. I was driving my car and the temperature gauge went all the way into the red and back to under the halfway mark and kept going back and forth. What would cause this?
A. At this point you need to determine if it is a gauge issue or the car actually overheated. If the car was actually running hot then the thermostat may be at fault. If the engine temperature was normal the problem could be a faulty temperature sender or gauge unit.
Q. I have a 1989 GMC Sierra 4wd with a 350 fuel injected engine. The problem is it often stalls, when warm, in drive with the brake on. This has become a challenge at red lights, Dunkin Donuts drive through and the bottom of my uphill driveway. My mechanic suggested replacing the EGR valve, I replaced it and it didn't help. I've owned this truck for years and its worth more to me than anything else. Any suggestion to help me keep my old friend running?
A. Your truck is exhibiting a symptom of a vacuum leak. At this point you are going to need to spend some time checking all the vacuum hoses looking for one that is cracked. A very common source of a vacuum leak on these older GM trucks is a collapsed PCV hose.
