Hello, My name is Jon and I live in Brandon FL. I have been a member for some time now but have not posted because I used the search feature and found some of the best information on the web.

My step daughter has a 99 Sportage and it has been a wonderful truck. A friend of hers was in a position that she needed a car and her family is non supporting and no help so my wife and I bought her a 97 Sportage 3 months ago for cheep because it needed a clutch. I did the clutch and got it up and running and all has been well until 2 days ago. She asked if I could take a look at it because it was shaking so I did. Well it felt like it was running on 2 cylinders so I started to check it out. To this point it has a flashing check engine light and codes for cylinder 2, cylinder 3 misfire, evap system, and o2 sensor. The O2 is not a big deal and I found a broken PCV valve and replaced it (not sure if broken PCV would be the Evap code). As for diagnostic work I checked and the timing belt is all spot on. I pulled coils and found oil so I did the valve cover gasket as well as spark plugs and used 2 other coils known to be good. After all this it runs the same on cylinders 1 and 4. I pulled it apart again and did a compression test on 2 and 3 and both checked out @180. I have tried 3 coils and all do the same. I checked for voltage at the coil 2/3 connector and got full battery voltage but not sure how to test this connector or if it should pulse. All and all I'm at my wits end and out of ideas. I heat to start throwing parts at it so any info would be much appreciated.

Sounds like a ignition, coil pack spark plug issue. It kinda sounds like the middle two plugs are grounded out. Before you start buying parts, take the to coils and plugs from the two cylinders that you know are firing and switch them with the 2 non firing cylinders. If it's a plug coil issue the two good cylinders will stop firing and the two bad will start working.

If that dosn't help shed some light start looking for a bad electrical connection, while the connectors may look good you'll need to take them apart inspect and clean them, and not just the plug and ignition connectors, you should check all related connectors in the engine bay. Also these engines can be very particular as to which spark plug you use. Some non OEM brands simply don't work well I always used OEM plugs from the dealer same with the coil packs.

zthis problem sounds very familiar, someone else had a simular problem in the past, so with some luck they will chime in. There is a nice sticky thread about changing the spark plugs that may help shed some light on the issue.

Good Luck

I have switched coil packs back and forth as well as checked connections and it did not affect anything. It will only run on 1 & 4. I put it back together without coil cover so I could test coil connection. With engine running on 1 & 4 and 2 & 3 unplugged I get a steady 13 plus volts at plug terminals.

mine did a similer thing but on #1 turned out to be the only thing i didnt change when i changed the coilsá it was the other plug wires!!!á <img src="/forums/images/graemlins/zombie.gif" alt="" />á could be worth trying mine looked good but were'nt. hope you figure it out <img src="/forums/images/graemlins/patriot.gif" alt="" />

I had the same problem, the wire harness to the coils can become brittle. you will get 02 readings it's raw gas going passed it because the plug is not firing. so if you tried different plugs and coils I would check out the harness.

Say pal,
What were the trouble codes exactly?

(I know u stated the signs and symptoms already) <img src="/forums/images/graemlins/kewl.gif" alt="" />

This would be a big ask, but you should be able to swap the ECU's between the two Sportages to see if it is the electronics drive to the coil that is at fault.

Failing that the only thing to look at would be the injectors. Could the injectors be clogged, causing the cyls to run lean? One bad load of fuel would be all it would take.

I will need to barrow the scanner again to get exact codes. Switch ECUs between the 99 and the 97 is one direction and I do not min the work but when looking for a used one on-line it looks like they are not the same. Can someone confirm both 97 and 99 ECUs are the same?

you much match numbers and letters, they must match

The ECM's from 1997 and 1999 are not compatible.

It sounds like you have an open cable between Pin 52 of the ECM (coil cylinder 2/3 output) and the coil itself. Yes, the yellow/white wire to the coil for cylinders 2/3 should pulse while the engine is running. If it reads full battery voltage with no pulse it's open, or it's possible that the ECM driver output is bad.

Check the connector to the coil carefully. Yes, those cables can get brittle over time. If that's good do a continuity check back to pin 52 of the ECM. The ECM is located under the passenger side carpet.

If you have good continuity it sounds like the ECM bit the big one.