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Very brief loss of power

2008 Honda Fit, 110k miles, new plugs. I’m driving along and it feels like I’m losing power (I think) for an instant. It’s very quick, so I’m not sure if I’m gaining power or losing it. When I feel it, it’s within seconds after shifting to a higher gear while accelerating (but not every time) or going up a reasonably steep hill while accelerating or constant speed. I never feel it going downhill or at constant velocity on a flat or slightly uphill road. Does anyone have a clue what is causing this?

I’d replace the fuel filter, if that hasn’t been done. That will definitely do what you describe and is usually an easy thing to replace.

I will follow your adventure. I am having the exact same symptoms with my 2006 Honda Element. I had the plugs changed for the 1st time at 150k miles and it the symptoms cleared for a few days. My check engine light comes on. The codes indicated misfires. I was starting to think fuel filter and revisit the as filter.

I spent the last day researching this and the culprit could be water in the fuel/clogged fuel filter, clogged fuel injectors, valve clearance, spark plugs, or coilpacks. I did my valves and plugs last month, so I’m ruling those out for now. Here’s my plan of attack based on cost and time:
Clean coilpacks, free and easy
Run a tank with iso-heet
Run another tank with fuel injector cleaner
Replace coilpacks, $65 ea
Replace fuel filter
Clean the injectors

Sounds like a plan. Report back as it may help someone else.

Sea foam, your new friend!

Might want to consider new plug wires too if it has them. They can start going south at that mileage.

Consider purchasing a new air filter, and test for a sticky EGR valve as a culprit too. If this happened after new plugs, you may simply have experienced the bad luck to have bought a faulty one; or, another common plug problem, not have the correct plug temp range. Are you using the exact plug manufacturer and model #, one specified in your owner’s manual or the shop manual? And did you verify the gaps match the spec before installing them? A failing cat can cause this kind of symptom too.

The air filter was replaced at the same time and the plugs are the NGK iridiums specified by Honda.

While I doubt changing the fuel filter is going to help with this trouble it certainly would be a good thing to do. I would suspect the fuel pump is really causing the trouble since the trouble seems to happen when extra power is needed. The fuel pump relay might be the cause also.

I believe I have the same problem with my 2007 Fit. A valve adjustment didn’t fix the problem. My mechanic has me using Shell gasoline exclusively. He suggested the medium octane, but I’m now backing off to the lower 87 octane grade. I do notice an improvement using Shell gas. I have since heard that Shell is consistently good and Marathon would be a respectable second choice.

Many Manufacturers Recommend “Top Tier” Gasoline. I Believe Shell Should Fit The Bill.
CSA

The problem was indeed the coilpacks. Unless you have reason to replace them (at $65 each), try cleaning them instead. To do this, grab the headpiece and the shaft and pull hard! When you get the two separated, you will see a spring. Using needlenose pliers, pull the spring out. You will probably see some white powder on the end of that spring and the nipple on where it makes contact with the headpiece. Clean that off with rubbing alcohol, let dry completely, and apply some dielectric grease on it and all other electrical contact points. Reassemble, reinstall, and you are good to go.

I just drove 240 miles in 2 days, up and down hills, in city and highway traffic, and the car didn’t hiccup once.

Thanks for the update.

Please, look at your ignition coils. this is a known problem. you said you researched it, there are lots of Honda forums on line that talk about this exact issue. Moisture is getting into the coils. Remove each 1 and seperate the coil pack from the conductive tube going to the plug, you will find corrosion in 1 or more of them. Honda has updated coils with drains that prevent this. I have bought coils off Amazon that cost a little less than Honda coils and are the updated style. Replace all 4. Your problem will be cured.

The codes indicated misfires.

Could you tell us what the codes were? <b> Like P0123</b>

My Element fared worse though similar symptoms. It ended up being burnt #1 and #2 valves. I had head and valves done. Replaced the timing chain and chain guides since the top engine was ripped part. Element running awesome. I blame myself. I noticed about 10000 miles earlier the exhaust was louder and less power on the low end. I just assumed it was the muffler finally failing after 135000 miles. I wish I had pursued a valve adjustment back then. Glad you had a cheaper Repair.

Just my 2 cents, but I have to lay the blame on Honda for your burnt valve problem. Honda, like other car makers that use mechanical valve lifters, changed valve lash inspection intervals from 15k miles to 30k miles to a 100k miles plus or infinity.
Most car owners luck out by following that bogus factory advice but for a certain percentage it leads to a major financial headache.

A good rule of thumb is to inspect and adjust valve lash as necessary every 30k miles.