My 2008 Honda Fit manual transmission with 100,000 miles was stalling when I would push the clutch in. It would stop doing it when the car was very warmed up. Dealer said it was a timing chain and wanted $1,200. That didn’the sound right but no other mechanic had a clue. I did a DIY search on the Internet and found someone with the same problem who adjusted the valves and the problem went away. I tried the same and it worked. I’m grateful my car is running great, but I really want to understand why this made a difference. Can someone explain it to me? Thank you.
If the valves were out of adjustment, say too loose, the engine won’t run quite as efficiently. That would mean the idle speed will drop and be too low to keep the engine running. Car makers set the idle as low as possible for mileage and emissions so even a small drop will cause stalling. Same for a stretched timing chain.
That is the simple explanation. Does that answer your question? I can give more technical detail if you want.
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In general the designers know what’s best for a car/engine, but sometimes the bean counters and marketers get in the loop and the end user is fed malarkey like “lifetime” transmission fluid.
Honda valve adjustment is a classic case.
The service chart for your Fit probably says to check the valves at 105k miles by listening for noise.
The reality is your engine will be happier and longer lasting if the valve lash is actually measured and adjusted to spec every 30-60k miles.
The valve lash affects timing of the valves opening and closing and can have odd effects on engine performance.
Worst case the lash on an exhaust valve can drop to zero and lead to a burned valve and an expensive repair.
BTW “tight” valves make no noise.
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Here’s a question for the OP: was there any valve noise (clicking, clatter) before you adjusted them? Did adjusting eliminate the noise? If not, it really supports several folks here who recommend more frequent adjustments, not just listening for noise.
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Ok, Accidentally replied to my own post.
The intake valves were way too open, but the exhaust valves were almost shut. I could not get the thinnest spacer in there. I guess I am lucky that it started stalling so that I knew that something was wrong. Thank you for the information.
Well, did it again.
What I am try to say is “Thank you.” You explanation helped. Now, if I can only figure out how to navigate this board. 
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There was no noise before I did the adjustments. Afterward, there was some clicking, which concerned me and I thought I did something wrong; but, the car ran so well and the gas mileage was like it was new so I haven’t concerned myself with it.
Thanks. We may use your experience to convince others to have their valves adjusted on a regular basis.
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I have a 1999 Honda Civic, bought new. Every 36,000 miles I replace the spark plugs and at that time adjust the valves. The car now has 174,000 miles on it and the engine runs perfectly. Every time, several valves had drifted out of adjustment.
The owners manual says valve adjustment is needed only if noise is present. That is simply very bad advice.
I am actually looking forward with pleasure to putting in new OEM plugs and adjusting the valves at 180,000 miles.
You’re lucky you caught the valve lash problems when you did; especially the exhaust valves.
Those have a tendency to tighten up due to valve stem stretch caused by heat from the exhaust of course and being constantly pounded on the seats. At some point the valves and valve seats will start burning and any fix will require cylinder head work.
As a matter of fact, it’s at least possible there could be some valve/seat damage now. It’s just not showing up currently but could appear in 20k miles, 50k miles, etc. Knock on wood this won’t occur. Just pointing out the possibility.
What would some of the symptoms be for valve damage?
Low compression
Hard starting . . . think excessive cranking, before the engine actually starts
misfires
Thank you. So far, running good after adjustment. Starts like a top and back to getting 35 mpg.
If it ever starts running a little rough in the future I would suggest having a compression test performed. If a cylinder shows to be low then the lash should be rechecked.
If the lash is fine then the prior tight running could be starting to take hold. Again, knock on wood there won’t be any issues and I’m just pointing out the possibility.
Some years ago on a motorcycle trip to Sturgis, SD I came upon a biker broke down in the sticks out in NE Colorado. I hit the brakes and returned to see if I could help. He was an amputee riding an antique Harley with a sidecar and also a member of a well known outlaw motorcycle club. I told him he could put the sawed off shotgun up he was holding underneath a blanket as I was there to help only…
He had a new engine just done before the trip and the valves had not been rechecked. The exhaust valves had tightened up during the trip and the engine had lost all compression on both cylinders.
Since I owned an identical Harley flathead back at home I offered to adjust the valves to see what would happen.
No go. Even after adjusting there was zero compression in both cylinders.
It bothered me to have to leave him there but he said no problem as some of his fellow club members would be coming along and they would pick him up.
It kind of illustrates how fast the valve and seat situation can go downhill when valves tighten up. In this case, less than a 1000 miles.