Setup is below, on the way to work this morning, i gave it some gas and the motor was slightly accelerating but bogging down during the acceleration. Sounds like babababababa. I have done nothing to it lately and its been reliable for the last 2 yrs now.
Preliminary diagnostic, No gas leak, problem isnt noticable until gas applied, vacuum is fine 20 at idle, air/fuel ratio reading tad high, engine temps fine.
Unfortunetly im stuck at work for the next 10 hours.;( If your car is sick does that count for sick leave?? lol.

 

Could be damn near anything...

Bad o2
Bad Map
Bad Spark Plugs
Bad Wires
Bad Rotor
Clogged injector
loose ground
etc etc etc etc.
Lose any of the above.

 

thanks man, ill eliminate the middle 3 when i get home tonight, in the aem ecu how would i know if my map is bad?

 

I meant MAP sensor... If everything was fine with the tune before it should be fine now... sounds like a sensor gone bad or wiggled loose... that's really the only thing that can cause such a sudden and drastic problem like that.

 

Heres the update, while bogging or stumbling, air/fuel ratios are getting leaner 15-16's. Pulled out plugs, feel very dry, and not smelling fuel like usual. Spark and compression are great down to the plugs, so im thinking fuel prob, I am thinking fuel pump. Its a Tre Performance high flow not name brand. I hear it wistlen at idle so works. but dunno how strong yet.

Curve ball though: The problem is really bad on my stock plugsngk zfr5f-11. However, on the ngk Iridium bkr6eix-11 plugs i had, it ran alot better but still stumbled at higher rpm. I have 2 pics the plug on the left is the stock plug. Look at the sut line on the arms of both plugs. the stock plug use to look like the one on the right.

IMO: Made the hotter iridium plug is burning the little amount of fuel its getting better then the stock plugs?

Please help honda gurus!

 

bump.. really need some help here guys.

 

bump because even though im all motor im having similar issues...my car has been running like crap lately, i havnt driven it in quite some time because ive just been working on projects but i always start it up and run it', although it is having issues similar to your's.. it mis-fires at higher rpm's and will studder down low with cooler plug's, if i use hotter plugs it only mis-fires at higher rpm's..i have also noticed my a/f is real rich down low and lean up top, i have no a/f ratio's to compare to sense the car was tuned, drove great for 6 months, then started with these issues, then months later i added the wideband, havnt driven it more than 20 miles sense it started these symptoms

someone mentioned the map sensor, is there a sure fire way to test the map sensor and see if it has gone faulty?

i have an omni power 4 bar map sensor here how-ever i wasnt planning on installing until the s/c goes on in a few weeks

i doubt its your map man, im going through the same thing, ive already replaced plugs, wires, rotor, cap, coil etc "im running msd"

 

sorry to hear about yoru problem man, My ignition seems to be working great as well. I am going to be working on this again tommorrow. Replacing the fuel pump with a stock one and see if anything changes. All 4 plugs have been pretty dry when pulled out. Im pretty sure this is fuel related. If you find anything out letme know i will do the same for you.

 

for sure, im going to check out the map sensor and tinker with that tonight'

im running a walbro 255 but ive never really had any problems with it, my fuel pressure is still on mark 42psi idle, 60 wot

ill keep ya posted

 

hey buddy check this out, I found the problem! Rotor cap, I just replaced it 9 months ago. So i kinda threw it out, I spent hours playing with everything and it turns out to be a rotor cap. Double check your or try another one, my is stumble completely gone! Very *** backwards considering i was runing lean!

 

Cou;dn't get to this quick enough. ALWAYS start with basics/cheap stuff first. Misfiring should have took you right to the ignition first, cap rotor, wires, plugs. Then go from there.

Glad you found it, and it was cheap though!!

 

thanks man, well i don't think it was a misfire because the motor wasnt shaking bad just stumbling. I pulled each plug at idle and would get the mis fire all across. But your right never elminate anything doesnt matter if it just came off the shelf. haha.

Can someone explain how in the world i would get lean readings if i had a super weak spark?

 

I warrantied it out, parts guy was trying to give me a hard time telling me it was my car, I said a rotor cap and rotor is suppose to last longer than 5k miles. Hell my oem one that i put back on has had 90k on them. Got to love OEM parts!

 

Frankly it doesn't make any sense... there's a decent chance that the new cap/rotor are just masking the lean problem..

I had similar issues with my 93 ex when I first got it used with 60k on it... I got the T belt changed at a dealer and it was fine... kind of a slug but it was alright... I had to change the plugs/cap/wires/rotor a LOT to keep it running well... it turned out the cam timing had been set a tooth advanced from the dealer...

Fixed it and the car ran like brand new again...

Chances are that's not your problem as it ran fine before... but I'd definitely take a look at replacing that fuel pump... could be that the new ignition components are just burning the lean mixture better than the worn out setup was.

 

just an update: actually i found the actually problem, its my accel wires, turns out the rotor cap didnt make a difference. But still don't understand why my motor doesnt run lean now but does with a bad/weak spark from the accel wires?

 

you get what you pay for?