Very recently, VTEC has lost its edge at 4700 rpm, I actually feel the car slow down. It feels normal as far as I can tell through the RPM range up to 4700. I did plugs/wires, cap/button about 4000 miles ago. Pulled my plugs yesterday, and they're aleady wiped out, just put in new plugs this morning, VTEC still sucks. Sorry if theres already an answer to this, the search is F-ed! This isn't a swap, stock engine, 112K, only have short ram intake. One thing that may be a contributing factor is a cracked exhaust mani. could this throw off my A/F ratio? I have a replacement on the way with the o2 still in it, which hopefully helps. I really appreciate any pointers...

 

Could be. Have you replaced the O2 sensor yet? 100k+ miles is a lot for an original sensor. Can you hear the vtec kick in? If not I would check the spool filter.

 

I have, but I am concerned that maybe the cracked exhaust manifold may throw off the a/f to the point where its shortening the lifespan of spark plugs, o2 sensors, and maybe the catalytic converter. I do hear the vtec, yes, its actually more noticeable than ever. I know typically, where I have stock exhaust, I really hafta listen carefully to actually hear vtec engage, now its very noticable, and you feel the car instantly lose power under vtec. Friggin wierd

 

Good idea to replace it, a cracked manifold is never a good thing. You should hear the vtec more with the short ram, but I imagine it's blowing like hell out of the crack. While you have the manifold off, take a look into the cat also. It could be melting down or clogged which would cause these symptoms also.

 

yea good call, unfortunately, its been cracked for a couple years, so the cat may have taken a beating

 

nobody has any ideas? ive seen some bright bulbs at HAN! help me out please!
this is my daily driver and i have to take it on a three hour trip outta state thursday. then its the three hour trip home that has me worried, please brainstorm with me. maybe some fuel/ignition issue? when the engine really demands air, fuel, and spark, one or more of those demands is not being met. am i so lucky as to be the first person this has ever happened to?

 

Yea, eliminate the obvious broken part first. If that doesn't solve it, then we can figure out things.

 

Definitely check the cat, when the engine demands more air to be sucked in, it also needs more air to be pushed out.

How is the oil level? Or maybe time for an oil change?

 

funny you say that, on my way home from work last night i experimented a lil bit and noticed i could actually hear the exhaust being forced through the crack from under the hood. it wasnt like that before, the only time i ever notice the leak from the mani was idle. so i pulled the cat last night and put in a straight-through p.o.s. that ive had lying around forever, and that was it! ol' girl goes like a bat outta hell again! so, if you go through those symptoms, you know what it probably is. thanx guys

 

Excellent.