Q. I recently had the thermostat replaced on my Chevy truck. I went to the dealer, and they confirmed what I suspected — the thermostat was bad. I basically just said, “Fix it.” When I picked up the truck, the bill was a little over $1,200. I haven’t worked on my own vehicles since college, but $1,200 for a $12 part seems excessive. Your thoughts?
A. On some GM trucks, replacing the thermostat requires removal of the engine intake manifold. That turns what was once a $100 repair into a $1,200 job due to labor time and additional materials. This isn’t unique to GM. For example, on some Ford Explorers the water pump is driven by the timing chain, so a leaking water pump often means replacing the timing chain, gears, guides, and then the pump itself. Another example is certain Volkswagen Beetles, where servicing the cooling fan or air‑conditioning condenser requires removing the bumper cover and both front fenders. Added engineering complexity like this can certainly take the fun out of a weekend DIY repair.
Q. My 2017 BMW 330xi has 24,000 miles on it. It’s in mint condition and has been maintained exclusively at the dealer. I’m getting intermittent pop‑up warnings for a cruise control malfunction. It appears randomly while driving—sometimes multiple times on a trip, sometimes not at all. It’s driving me crazy, but it doesn’t affect drivability. I know that if I take it to the dealer, even the diagnostic inspection will be expensive. Any ideas to save me a trip?
A. Unfortunately, this is one situation where you’ll need either the dealer or an independent shop with a BMW‑specific scan tool. Cruise control faults can be triggered by a wide range of issues. A good starting point is the battery — BMW electronics are extremely sensitive to voltage drops. A battery that’s strong enough to start the car but slightly weak can cause random system warnings. Other possibilities include a failing wheel‑speed sensor or an intermittently faulty brake‑pedal switch. If the car is equipped with front radar or driver‑assist features, dirt on the sensor or a slight misalignment from a parking‑lot bump could also be the cause. At this stage, a proper system diagnosis is unavoidable.
Q. My 2011 Ford Mustang with the 3.7‑liter V6 had poor performance, very little power, and the check‑engine light on. A scan revealed a P0022 code, and Google suggested a VVT solenoid issue. I took it to my long‑time mechanic, whom I consider honest. He diagnosed the car and said the solenoids were fine but the timing chain was worn. I paid his diagnostic fee. After letting the car sit, I decided to try another shop. They also wanted to perform diagnostics. The next day they called and said, “We think we found it” — a bad solenoid. They replaced it, and the performance returned to normal. I went back to my original shop and explained what happened. They took no responsibility, saying the solenoids tested fine and led them to suspect the timing chain. In your opinion, should the shop have handled this differently—perhaps compensating me or at least placating me? Is the lesson here that big jobs deserve a second opinion?
A. Yes — when facing a major or expensive repair, whether it’s automotive, home repair, or even healthcare, getting a second opinion is usually wise unless the technician is absolutely certain. There are multiple ways to test a VVT solenoid: resistance checks, activation tests where power is applied to confirm operation, and analysis of live scan‑tool data. If only a partial test was performed, it’s easy to be led in the wrong direction. Unfortunately, admitting a diagnostic miss doesn’t come easily for many people. If it were me, I might have said, “I’m glad the car is fixed. These solenoids can fail due to dirty oil—how about we cover your next oil change.”
Q. I would like your advice about a problem with my 2016 Audi Q5. While driving on the highway at around 75 to 80 mph, the car started shaking. The check‑engine light came on, followed by the EPC light. After that, the engine shook at idle and sometimes took longer than normal to start. Later, when I moved the car a short distance uphill into my driveway, the check‑engine light began flashing for a few seconds, then went solid again when I put the car in reverse. The car is now parked, and I’m not driving it. Does this sound like an engine misfire? Is it unsafe to drive? Should I have it towed directly to a mechanic?
A. A flashing check‑engine light indicates an active engine misfire. The EPC (Electronic Power Control) light points to a fault within the throttle or engine management system and often accompanies misfires. Driving the vehicle in this condition risks additional damage, including potential catalytic‑converter failure. I would have the car towed rather than attempting to drive it.
Q. I own a 2021 Chevy Colorado with an automatic transmission and a four‑cylinder engine. The truck has only 37,000 miles. In December of 2024 it overheated and had to be towed to the dealer. A freeze plug was replaced, which was expensive mainly due to high labor costs. While I’m not impressed with the build quality, the truck’s size suits my needs perfectly. Recently, I noticed a shudder during acceleration and downshifts. My research suggests this model has torque‑converter issues, and that a transmission fluid purge may help. Do you think I should try that first? With today’s exorbitant used‑truck prices, I want to fix rather than replace it, but I can’t help wondering what’s going to fail next.
A. A fluid flush may help, but I would also want to inspect the transmission pan. Debris in the pan can provide valuable insight into the transmission’s overall condition. It is well documented that these transmissions have had ongoing issues with torque converters and valve bodies. Aggressive fluid flushing can also loosen more debris which can lead to additional issues. While I’m generally not a fan of chemical fixes, when facing a potential $3,000‑plus repair, I would consider an additive. For transmission shudder complaints, Lubegard Instant Shudder Fixx is one option worth trying.
Q. My 2016 Honda CR‑V is overdue for spark plugs at 109,000 miles. Should I spring for the expensive NGKs, or save money with a less‑than‑half‑price U.S.‑made brand (MODIGT) I found on eBay? Do I need a thin‑wall socket for these plugs?
A. I know the NGK plugs — at about $45 each — are expensive. Even at the risk of being called cheap, that’s still the plug I would use. Afterall, you’re replacing them only once every 100,000 miles. Yes, you will need a thin‑wall 14 mm spark‑plug socket. I’d also recommend replacing the spark‑plug tube O‑rings if there are any signs of wear.
Q. When I plug my iPhone 17 in, sometimes Apple CarPlay connects to my Toyota Camry and sometimes it doesn’t. The phone always shows that it’s charging. My sister has the same issue with her Honda. Why can’t Apple CarPlay consistently connect to our cars?
A. We’re seeing more technology‑compatibility issues as vehicles and phones evolve independently. It often seems that every time an iPhone operating‑system update rolls out, something that once worked suddenly doesn’t. If your vehicle supports over‑the‑air updates, make sure it’s fully up to date — and do the same with your phone. Staying current on both sides offers the best chance for reliable connectivity, even if it doesn’t guarantee it. Additonally if you are using a cable to connect to your car, Apple phones tend to be very fussy about cable quality. Using an Apple brand cable is always a good choice.
Last updated on April 28, 2026 by AAA Staff
John Paul is AAA Northeast’s Car Doctor and a nationally recognized expert in automotive technology and repair regularly answering reader questions in columns published across the region. He began his career as an automotive technician and attained ASE master technician certification more than 40 years ago.
Do you have a car question? Email the Car Doctor for a personal reply: jpaul@aaanortheast.com.
