240sx mising out at high rpms

[rickboy240sx]

I just recently did a full tune-upwaterpumpcap n rotorplugs n wiresfuel filter1 fuel injectori'm running straight pipes right now.... i put one on and it till did the same thing. It's hard to explain but here i go.When i first start it up it runs fine. after it ges up to temp it misfires when i press the gas 1/2 to 3/4 of the way down. i thought it may be the timing so i got a timing gun and ajusted it. it still back-fires mis-fires and idles like shyt.

would it be an o2 sensor...i'm not throwing any codes

[s13_maJiK]

Oxegen sensors don't cause missfires, a misfire will cause the O2 to have a "False Lean" condition, a false lean is what happens when a misfire occures the unburned oxegen de to the misfire goes threw the exhaust past the O2 and reads it being lean thus making the car run richer.

[MikeyCee]

Mmm ignition timing? check the distributor i suppose.

[liquid_cool]

you might have crossed plug wires man..check those then your dist cap and if all else fails..start pining out sensors.

[blackRB240]

Fuel problem, possibly? Check your pump and strainer lately?

[Gabes13]

dizzy might be off a tooth..... or not

[rickboy240sx]

I checked the timing and it's in time. I'm thinking it might be something more serious because the engine has over 180,000 miles on it. I also noticed that it idles at like 1500 when i first start it until it heats up. Then i'll sit and idle it misfires and sometimes shut's off. I just bought new spark plugs and number four has some oil on it. I'm gonna do some compression test. Does anybody know what good compresion on a ka is supposed to be?

THe spark wires are in the right order cause my buddy put em' on bass akwards a few weeks ago and i made sure they were right..... It doesn't misfire all the tme just when i push on the gas tryin to get on it. irst and second gear is the worst. It's really challenging trying to drive it but i still manage to keep it from misfiring a little.

[rickboy240sx]

Fuel problem, possibly? Check your pump and strainer lately?

i might have to look into that. I just replaced one fuel injector because i was running on three cylinders. I replaced the fuel filter too. so the only logical place to look for more fuel problems. Is there any way of checking the pump without dropping the tank. i dont remember if theres a whole in the trun or not. , thanks for the idea's ppl

[Gabes13]

oil might be caking on the spark plug and preventing it from firing. Im having a similar problem but really dont care b/c im going for a rebuild in the summer

[needmorenissan]

I checked the timing and it's in time. I'm thinking it might be something more serious because the engine has over 180,000 miles on it. I also noticed that it idles at like 1500 when i first start it until it heats up. Then i'll sit and idle it misfires and sometimes shut's off. I just bought new spark plugs and number four has some oil on it. I'm gonna do some compression test. Does anybody know what good compresion on a ka is supposed to be?

THe spark wires are in the right order cause my buddy put em' on bass akwards a few weeks ago and i made sure they were right..... It doesn't misfire all the tme just when i push on the gas tryin to get on it. irst and second gear is the worst. It's really challenging trying to drive it but i still manage to keep it from misfiring a little.

it should be 180 for a good engine but above 150 is fine

[lukbot]

could be the coolant temp sensor. worth checking, pretty easy. will cause a miss when the car is warm nut the computer still thinks it is cold. and make it idle high at startup.