A Georgia mechanic took to TikTok with a warning for used Honda shoppers. He says a range of six-cylinder Hondas, including the Pilot, Odyssey, and Accord, might be prone to pricey, irritating misfires and engine codes. 

A certified mechanic at a shop in Georgia outlines why some used six-cylinder Honda vehicles were a ‘blemish’ for the brand

A mechanic at Royalty Auto Service had a stern warning for viewers as he worked on a 2014 Honda Odyssey minivan. With the hood open, the mechanic picks up two spark plugs and shows them to the camera. He says the 111,000-mile Odyssey recently had a spark plug replacement. As such, both plugs should look pretty good. The problem is that they don’t. 

One cylinder’s plug is clean, with the white porcelain still visible and a healthy center electrode. On the other hand, the third cylinder’s plug was ugly and oil-fouled. “I love Honda. They’ve always made great cars,” the mechanic said. “This is a blemish to me.”

The certified mechanic then says the oil-fouling and misfiring culprit is Honda’s 3.5L V6 engine covering the span of 2008 through 2014. That’s many used Honda Accords, Pilots, and Odysseys. Most of the eighth-generation engine’s tenure, really. Incidentally, the mechanic points out that Honda extended the warranty on some of these vehicles. 

But according to the Georgia mechanic, owners had to prove it. For starters, a driver needed to have a misfire and a resultant code. He said owners would take their Hondas to a service center with a code, technicians would pull the fouled plug, and replace a few. They would also reprogram the vehicle’s ECU. 

However, the mechanic says the fix wasn’t much of a fix, because the oil-fouling and consequential misfiring was due to failing piston rings. “You’re not fixing rings with a reprogrammed [computer],” he said. He argues that the factory warranty extension may have sounded nice, but many failures occur outside the window.

However, a handful of Honda-savvy commenters posted to remind readers about one of the Honda V6’s best aftermarket allies: a VCM muzzler. In certain Honda six-cylinder engines, the Variable Cylinder Management (VCM) system works like other brands’ cylinder deactivation facilities. A muzzler disables the function, and in turn, reduces some of the risks of misfires.