Q: I have a 2004 Chevy Blazer with a 4.3-liter engine, four-wheel-drive, with 201,000 miles. It runs like new, but there’s one minor problem: When I go on the highway or up a steep hill and push hard on the gas pedal, the engine knocks once and the service engine flashes, say 25 to 30 times, then goes off. It’s so awkward and started about six months ago.
A: Scanning the engine, you will probably find misfires on cylinders one, two, three and four. This is caused by water intrusion into the spark plug chamber at the spark boot. This water intrusion is caused by a bad hood seal near the windshield. GM does make a new seal as part of a technical service bulletin. You will need to replace the plugs and coil ends if they are contaminated.
Q: I read your column every week in The Salem News, even though I depend on the dealer where I purchased my car. I would like to have you put in the date code for tires and explain how to read it.
A: On the side of the tire, you will see numbers that look like they were branded on with an old-fashioned branding iron. Since the year 2000, the week and year that the tire was produced have been provided by the last four digits of the tire identification number, with the two digits being used to identify the week immediately preceding the two digits used to identify the year. For instance, if the stamp reads something like FLRR 5007, that means FLRR is the manufacturing plant, 50 is the 50th week, and 07 represents 2007. So, this tire was built at the plant designated FLRR, during the second week of December in 2007. I hope this helps.
Q: I’m looking for help with my 2005 Hyundai Santa Fe with 116,000 miles. It started having a problem about a month ago. Whenever I get fuel, the car starts hard right after fueling. It acts like it lost its prime. It needs several starts to keep the engine running. Other than these times, the car starts and idles just fine. I don’t let the gas tank get below half. It doesn’t matter whether I fill the tank or put in $20 or so to get it to three-quarters. No check-engine light. Yesterday, it took several tries to keep the engine running. The car ran only a few minutes to home and something else occurred; it wouldn’t shut off when the ignition turned off. I quickly flipped the switch back on, let the car idle for a couple of minutes and then tried again — the engine stopped right away. No fumes, no black exhaust smoke, no rough idling, no hard starts at other times — just when I put in fuel. Could a leak in the evap system have anything to do with this?
A: The problem is an open check valve (purge valve) at the fuel tank. Scanning the system with a bidirectional scanner will reveal this problem.
Larry Rubenstein is a master technician who owns a North Shore service station. His column appears every Saturday. Write to Larry at The Salem News, c/o Auto Scanner, 32 Dunham Road, Beverly, MA 01915, or send an email to firstname.lastname@example.org.