Q. I have a 2005 Toyota Corolla. It did not receive an inspection sticker because of a check engine light code. I took the car to a local dealership and they said the car needed to have the PCM replaced. They stated it would take 3-5 days to get the part. That was on April 14 and no sign of the part expected until after May 8. They are waiting for 12 of these and Toyota is shipping 2 of them. The dealership said they have 3 cars on the lot waiting for this part that don’t even run. I contacted Toyota and first was told that the parts had been shipped to the Toyota parts depot. Then they changed their answer. There are 1600 of these PCMs on back order countrywide. I think this a known defect but couldn’t find any reference to it. This is not a dealership problem. This goes back to Toyota. So much for Toyota reliability. The part fails and then you can’t get it replaced.

A. This is a problem that is effecting certain 2005-2007 Corolla, Matrix and Pontiac Vibes. You have 60 days from the time of your inspection until your rejection sticker is no longer valid.

Q. I have a 1998 Honda Civic DX Hatchback. There is a problem with the speedometer. It is stuck on 20 miles per hour most of the time. Sometimes it works, but most times it does not. When I drive 75 or more miles it kicks in and works all the way. Do you think the problem is a speed sensor (which I changed two years ago) or a speedometer it self?

A. The speedometer receives its information through the vehicle speed sensor. Since the speedometer works some of the time, it is possible the problem is a loose connection or poor ground circuit. If this is not the case then the likely cause is a faulty speedometer.

Q. I have a 2003 Honda Accord. The wipers quit working and the dealer is telling me the relay that controls the wipers is blown and the entire fuse box under the hood has to be replaced. The cost is about $600. Is this true that the entire fuse box has to be replaced?

A. It is possible that the fuse block may need to be replaced if it was damaged by a short circuit. I would be concerned about what caused this problem, damaging both the wiper-control relay and the fuse block. Replacing the fuse block and relay without finding the cause of the problem will surely lead to a repeat of the same incident.

Q. In the last few weeks, my 2000 VW Cabrio has started stalling and hesitating whenever I shift up to second gear. It behaves as if the fuel injectors are clogged, but obviously if that were the case this wouldn't only happen when going to second. Other than that, the car could not run any better. Any idea?

A. The first procedure that should be performed is a check for computer fault codes. The computer can store intermittent faults that may not turn on a “check engine” light. The one part that in my opinion may require a little extra scrutiny is the mass air-flow sensor, which has been known to cause similar symptoms. 
 
Q. I was on a trip with my 1997 Isuzu Rodeo and had driven about 50 miles. The car started "bucking" but no lights came on. I pulled off highway and the car barely got to a service station. If I stepped on the gas the car bucked, had no power and backfired. The mechanic put the car on a diagnostic machine, but by the time they looked at the car it was running fine. I asked that they change the fuel filter, which they said was real bad. I drove about 20 miles and it started again, although not as bad – you can feel the car "losing power" (surging is perhaps a better word to use). It ran OK at 55 mph but if I tried to step down on it to go into "passing gear" it just died out. Around town it is fine. Do you have any suggestions before my next long trip?

A. Since the fuel filter solved much of the problem, the next step would be to check the fuel pump for both pressure and volume. Once that is completed have your repair shop check for a possible restriction in the exhaust. It is possible that one of the catalytic converters is starting to plug up.

Q. My 1997 Pontiac Grand Am SE is making a loud sound like metal scraping against metal while the car runs, but as soon as I turn on the AC fan, the noise is gone. Can you tell me what the problem may be before I take it in for repair? I always seem to get "taken to the cleaners" by auto repairs.

A. When the air conditioning is cycled on, the compressor clutch is being engaged. When the compressor is energized, an electromagnet draws the clutch to the pulley and drives the compressor. From your description it sounds as if the compressor clutch plate is worn.

Q. My 2001 Pontiac Sunfire recently had something strange happened. The headlights and the windshield wipers won't work. The fuses have been checked and they are all fine. The other strange thing is when you put the headlight switch on the radio turns on without the key in the ignition. Your help in this matter would be appreciated. Anthony

A. Whenever one accessory becomes energized without specifically being turned on, the most common problem is a faulty electrical ground circuit. At this point you need a technician who will trace the wiring to look for the fault.