I am having a problem with my 93 240sx

[knx2]

I was in the process of a tune up on my 240sx replacing the plugs, plug wires, cap and battery

The car was running great for a couple of days and now the idle has dropped down to 500 rpms. Also the forth cylinder has stopped firing. With the engine running I pulled the wire off and i could hear the spark but no change.

I would like to know what other tests or things to check. I have searched the forums but have not found my answer.

[DjPantsSpecR]

ha, my 93 240sx has also developed a problem this evening

is it stalling? i think its probably a good idea to check injectors. if one is dead it will run and idle like just crap. it will sound like a diesel and have no power.

its easy to check the resistances for a dead injector, but not so easy to check for a stuck injector

also consider the iacv or the pair valve, but i would focus on the IACV valve on the intake manifold, search around for that, and also check to see that the throttle body is nice and clean

[Ni2s4s0aSnX]

Normal idle on the KA engine is around 650, just letting you know that. But are you sure that the 4th cylinder isn't firing? Is it running really rough and/or stalling out? You may just have gotten a plug dirty or something when you replaced them. Also, check your fuel injectors.

[knx2]

This morning my car runs fine. I am going to check the injectors tonight.