NasTHatch

2003 s2000 currently having misfire issues upon hard acceleration,I just installed new NGK plugs, and the valve adjustment was done same time, codes are misfire cylinder 1/2/3/4/ and multi-cylinder misfire detected. Tested all 4 coils with a coil tester and they all work, stock air box, aftermarket header and exhaust with stock converter.

Upon normal acceleration in any gear nothing happens, but a hard high rev pull in 3/4/5/6th will cause the light to blink and then stay on, all plugs were gapped to .043 indexed and torqued to spec.

Any ideas?

smilin dave

Was the coil tester verified as good? I have has problems with some plugs, not those, but some brands have too broad heat range for some systems. Try going with another brand and test, cheaper than throwing expensive parts at it. Did anything else change? Were the valves adjusted at absolute no heat conditions? I try to do them before the car is moved after an overnight cool off, had issues with a race engine years ago not being truly cold. Let us know.
Regards
Dave

NasTHatch

Car sat for a week before the adjustment was made,plugs were NGK from Honda and two different brand testers were used

smilin dave

Well,
That is all of my knowledge in a nutshell. I hope someone else has an idea. Sounded like a coil breakdown to me. Coil on plug systems can be strange at times.
Regards
Dave

NasTHatch

Found a TSB on the TPS wiggling under hard acelleration and the suggested repair was the replace it and install a zip tie, so I installed the zip tie today and going to see what happens

Scotty_Nooo

Sounds like what a civic i got to flip was doing, ended up being a bad exhaust valve. A quick comp test will tell you if that is the issue.

Not too sure how the timing on those engines work but i know with the old B series stuff if the Crank Positioning Sensor went tits up that would cause a misfire across the board too.

NasTHatch

Compression is solid, that was checked, installed a new Honda sensor and their zip tie, still getting the misfire codes, I'm going to have Honda take a look at it

smilin dave

Allright, this is killing me! WHAT THE HELL WAS THE CAUSE!!!!! I would like to tuck this away as learned, BUT ONLY IF YOU TELL ME ALL READY!!!!!! Please tel me the cause, I think it could be the crank sensor failing however I am not sure.
Regards
Dave

NasTHatch

Still have not determined the cause, installed an OEM map sensor with the sensor strap per Honda, swapped plugs and coils with a friend, tested every sensor and still get the same end result,which is now becoming more frequent, low or high speeds when driving normal or even hard acceleration, and the check engine light flashes longer now, before it would flash 3 maybe 4 times, now it will flash up to 10 times.

Boosted.

I have a friend that had the same problem as you. It ended up being his ECU, and once he bought another used one and put it on it stopped the problem.

I would try that, or check your timing.