Q & A #64 With The Auto Specialist
Q & A #64 With The Auto Specialist
Thanks for joining me for the latest installment of the Auto Specialist. If this is your first time visiting, I’d like to encourage you to take a peek through our archives. Over the past year, we’ve put together an impressive library of automotive Q&A that sheds light on an assortment of car problems. From failing alternators and transmissions to fuel pumps and catalytic converters, we’ve covered it. If you’re experiencing trouble with your vehicle, you’ll likely find the problem has been diagnosed in a past installment.
Today, we’re going to take a look at a misfire that Jason is experiencing with his Accord. We’ll also help Cameron figure out why he’s unable to start his Continental. Lastly, we’ll help Saul with a question he has about his Infiniti QX4′s rough idle. It’s a full docket, so let’s get started.
Question: I have a 2000 Honda Accord with 137,000 miles on it. Over the last week, I’ve been getting a random misfire while driving. It happens both on city streets and at high speeds while I’m on the freeway. Here’s the thing: I’ve done a lot of troubleshooting. I’ve replaced the spark plugs and plug wires, done a compression test, and even checked the manifold absolute pressure sensor. I’ve also gone through the ignition system and looked for trouble codes (I have an OBD-II scanner). Everything seems to check out fine. Can you give me any hints about what may be causing the misfire? Thanks.
Answer: Thanks for sending in your question, Jason. It sounds like you’ve done a good job troubleshooting. Given that everything you mentioned is checking out, I’d say the problem might be with one of your fuel injectors. Occasionally, the injectors will short out and stay open, allowing fuel to flood the cylinder. If that’s the case, replace the injector and the misfire should disappear.
Question: I’m driving a 1999 Lincoln Continental. I replaced the engine about four years ago and the mileage on the new assembly is at 65,000. I’m having trouble starting it. I tested the battery and it seems fine. It’s putting out plenty of voltage. Any idea what might be the problem?
Answer: Thanks for your question, Cameron. There are a lot of factors that might cause a no-start situation. It could be something in the ignition system (for example, the switch, starter solenoid, starter motor, etc.). It may also be a problem in the fuel line.
Here’s what I recommend: first, pull the trouble codes from your powertrain control module (you’ll need access to a scanner). Second, check to make sure the timing belt is fine. Third, test the pressure in your fuel line to verify your engine is receiving sufficient fuel. Last, test your spark plugs. Most no-start cases can be traced back to those items.
Question: I bought a 2002 Infiniti QX4 a few years ago. It has a little under 94,000 miles. Starting a few months ago, the car began to idle roughly and hesitate when I tried to accelerate. It didn’t happen very often at first, but it happens a lot more frequently now. The technician at my dealership tried to get me to agree to a long list of repairs. But I have a feeling that’s unnecessary. What do you suggest I do?
Answer: Thank you for writing in, Saul. When it comes to engine problems, the best place to start troubleshooting is at the powertrain control module. Invest in an OBD-II code reader (you should be able to buy one online for under $40), and use it to pull trouble codes. I’m surprised the tech at your dealership failed to do this. The codes are a bit vague, but you can find their meanings online. That will point you in the right direction.
That’s it for today’s installment. Thanks again to Jason, Cameron, and Saul for giving us an opportunity to help diagnose their automotive problems. We’ll be back next time with another group of questions, so be sure to join us. Until then, drive safely.
