Random drag then let go at highway speed
 

Hi guys,

I've noticed driving home on the freeway some peculiar behavior.

With speed and throttle position constant, on an unchanging road grade, it will once or twice feel like the AC compressor kicks on for a half a second.

Thinking I was hallucinating I started keeping an eye on the live MPG display and it drops from low to mid 50's down to 40 even for about a second, right in conjunction with the drag, then almost as fast, jumps back up to where it was.

I know the IMA motor works as the alternator also but to my knowledge nothing is changing electrical load, typically I've been driving for 5 minutes without any assist so I doubt its the battery fan kicking on.

I'm on the highway doing 65MPH with everything off except the headlights, drain should be constant.

Any guesses what this could be?

Re: Random drag then let go at highway speed
 

The only thing I can think of is a purge cycle. They can't lean burn forever, so they periodically richen the fuel mixture to purge the accumulated lean burn products from the cat.

I've never heard of it being so pronounced, but that's my guess.

Re: Random drag then let go at highway speed
 

hmm, that does make sense, and the conditions it appears to be doing it -- im not a mechanic, (though I am pretty hand) but they sound like they would be the time the ECU would decide to do it.

Its possible i'm just hyper sensitive since I've had issues lately,....

Once work calms down fro 45hr weeks and school is out I'll pull the ignition system and evaluate it.
I'm curious if one could have up to 4 bad coils hidden by the fact that there are still 4 good ones.

Still sounds pretty neat as it goes from open to closed loop at idle though.

Re: Random drag then let go at highway speed
 

Not sure if it applies, but my HCH2 with 1 bad coil was not masked by the other coil. I could feel the stumble.

Re: Random drag then let go at highway speed
 

That is useful data! Thank You!

Re: Random drag then let go at highway speed
 

The coolest thing was to have two cars of the same year, and color even... I just starting swapping coil packs until the problem moved to the other car... :)

Got away with replacing only 1 of 8.

Re: Random drag then let go at highway speed
 

Dude thats freakin great! hahah
Maybe I can see if Wifie's 08 Fit has the same coils. I wasn't able to determine which one (or more than one) it was so I ended up having to do all 4... but now I have my control group!