goodspeed

um... stop spending money on parts you dont need.

to get a car to run well, you need 3 things.

spark, fuel and compression.

Since your compression should be ok the only thing you got to worry about is fuel and spark.

Since your car is running fine in higher RPM and since it drives, its probably not the fuel.

Only thing you gota worry and trouble shoot right now is spark.

Get a manual and do a spark trouble shoot walk through.

Since the S2Ks use coil packs im guessing since i never needed to open mine, you can test the resistance for the coils individually.

Not sure the specs but off the top of my head, they generically should not be more then 15ohm resistance when cold.

Test these, find the one that is bad. Check all the connections to make sure they are all on snuggly.

Also check to make sure the spark plugs are gapped correctly as they dont usually come pre gapped.

For the love of god, stop throwing money replacing good parts. Let me know if you have more questions.

It has nothign to do with your driving habbit... i dont know how you drive but these cars are made to be driven. Dont listen to the wild guesses that send you on a wild goose chase.

ek9k24

i think its only one bad cyl...
iam thinking bad injector...not closeing all the way..
find out which cyl is bad first..
when the car is mis fireing on idle take the coil cover off and disconnect or remover each coil one by one untill you find the bad cyl...you will know when you find the bad one...there will be no diff in the cars idle and mis mifire ewhen the coil is removed..

Stko0k

one of my uncles has a junkyard....he said come down i will give u some oxygen sensors..he has many honda/acura sensors....he has many plugs with the 4 wires that are VERY clean....are the 2 oxygen sensors different on a S2000? or can i just pick 2 of them up that look identical to stock ones.....the reason i want to change these is i had previously hooked up a universal one and had cut some wires and we did the wires...and if i take it to the dealer and they say ur wires r cut and re-connected....they might say well thats ur problem which it really isnt......so i was just wondering if any 4 wire honda plug would work on my car

Stko0k

I changed my oxygen sensors to brand new ones from the dealer.....the car drove fine for a day or 2...and all of a sudden started missfiring again...when i first turn on my car in the morning the idle starts acting very funny it jumps from 100 to 900 back and forth and almost dies...or it just turns off.....could a TPS sensor or a bad IAC cause a missfire?

Stko0k

Finally got a check engine.....got the same one as before - System to Rick Bank 1. however i got another one with that one (P0170) fuel trim malfunction....any ideas anyone?

Ek9

It's pretty clear you have a mixture problem. Fuel trim is how the ECU controls the mixture. It's probably driving the engine full lean and still not getting the right readings on the O2 sensor . The first thing to check is fuel pressure. If that's wrong you need an FPR. You didn't stick an upgraded pump in this thing did you? Too big a pump, the FPR can't regulate fuel pressure. Then I'd pull the plugs. If you're right and one injector's bad, you should see one cylinder where the plug's black and the rest should be normal.

If the fuel pressure's correct, you need to check the temp sensors. ECU runs the engine rich when cold. If the sensor's bad and it never detects warmup then it'll probably run rich all the time. MAP sensor also applies.

From my understanding, TPS is only used to determine a rate that the butterfly's opened, it's not used for mixture. Rather the map and O2 sensor is used for calculating the mixture (speed density). The IAC is a small adjustable air bleed for setting the idle speed. It also doesn't have much affect on mixture.

If you're not using an OBD2 scanner (not code reader), you're just wasting your time. It would tell you in 10 seconds which sensor's getting bad readings.

You have to keep in mind, if you're car's running way rich, you may end up screwing up the motor. Too much gas washes the oil off the cylinders and all of a sudden you have a worn out motor. I wouldn't drive it much like this. Since you don't sound like you have the tools to fix this, I'd take it to a shop and hope you haven't screwed the engine up.