Did I Do Any Damage To My Engine?...

[fnutz09]

Hi Eveyone,

I just finished changing the spark plugs in my 98 SC400...I did not want to pay the dealer around $200 in labor just to change the plugs (I had already purchased Denso IK20 Iriduim Plugs)...

So, after about 3 hours I finished the task...not as bad as I thought it might be... I started the car and immediatly I noticed it idled rough (extra vibration from the engne)...

I thought maybe the ECU needed to get used to the new plugs so I took it for a little spin (about 3 miles round trip, during which I punched the gas twice, once each way)...after about the first 1/2 mile the Check Engine light came on and on the way back it started to blink...by the time I got back to my house it was idling very rough almost ready to stall...

Well I started to relally freak out :( ...What had I done to my baby...

Well, after a closer inspection it turns out I forgot to connect (1) of the connectors to the spark plug coil...

I re-started the car and it idled perfect again...although the Check Engine light did NOT go out...So, again I did my same 3 mile round trip and the car ran perfect..but the Check Engine light did NOT go out...

So, I pulled the neutral on the battery..waited about five minutes and finally the Check Engine light went out (AMEN)... :D

So...My question is did I do any damage to the Engine by driving it for about 3 miles on 7 cylinders?..I really do not want to pull that spark plug out again if I don't have to or should I just replace that plug...

[bartkat]

Probably didn't hurt anything. If the plug got fouled and it's firing now, it should burn itself clean. If it's running ok and no CEL you should be fine.

[fnutz09]

Probably didn't hurt anything.  If the plug got fouled and it's firing now, it should burn itself clean.  If it's running ok and no CEL you should be fine.

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Thanks...barkat

[SKperformance]

No problem it will run with one plug not firing easily.

[fnutz09]

Probably didn't hurt anything.  If the plug got fouled and it's firing now, it should burn itself clean.  If it's running ok and no CEL you should be fine.

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Thanks...barkat

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Could the unburn fuel going thru the one cylinder and out the exhaust have done any damage to the catylic converter?...or would the CEL light have already come back on if that was the case?...

[DomLee]

For that short period of time, your cat is fine.