Questions and Answers

Kia Sephia Is Missing Q. Sir, I have a 2000 Kia Sephia with a1.8 liter DOHC engine, automatic transmission, A/C and P/B. Recently, it has started to run very rough. It acts very much like it is missing on one cylinder. It has low power, and an inconsistent idle. Sometimes the idle is fine, other times it is rough (again like it is running on three cylinders). I changed the plugs, and they were worn, but it had no effect.

I have noticed, that when driving, it runs fine, if I use virtually no throttle. (downhill, just touching gas). As soon as I start up hill, or anytime I touch the gas (more then just a little bit) it again starts to act sluggish and like its missing. At this point I suspect it's either A) a bad fuel pressure regulator or B) a bad injector.

Do you have any comments? I'd prefer to do the repairs myself, but I have little fuel injection experience. Without a scanner, I'm unsure of a better way to diagnose this problem (the dealer refuses to show me the results of a diag scan, unless they do the repairs)

Thanks!
Mark

A. Did you look at the spark plugs when you took them out? They will tell you a lot about the cylinder they were in and what kind of health it's in.

Before I go looking for a problem with the EFI system, I would recommend replacing the distributor cap, distributor rotor and ignition wires. They are more likely to be bad than the injectors.