Replaced Plugs With Iridiums And Misfiring?

[DisasterBUSE]

I changed all spark plugs on my GS400. I used the NGK Iridiums. For some odd reason my car is now misfiring or something. I feel a small stutter or pop outta my exhaust and a bump inside the car every few seconds at idle. What would this be from. I checked the gaps on the spark plugs and they were just fine. Someone help!!! Its annoying.

[GuyTelefunken]

What part number did you use? Lexus specifies an NGK IFR6A-11 which has been replaced by the NGK IFR6T-11. If you did use the correct plugs, you may have possibly gotten a bad one. If you have a scantool available, you could go into the misfire counter and see if there is a problem with a particular cylinder. If there is a problem in multiple cylinders, it is likely that your engine just doesn't like those plugs.

Can you tell which plug was installed before you replaced them? The other recommended part is the Denso SK20R11, replaced with the current Denso IK20.

[DisasterBUSE]

What part number did you use? Lexus specifies an NGK IFR6A-11 which has been replaced by the NGK IFR6T-11. If you did use the correct plugs, you may have possibly gotten a bad one. If you have a scantool available, you could go into the misfire counter and see if there is a problem with a particular cylinder. If there is a problem in multiple cylinders, it is likely that your engine just doesn't like those plugs.

Can you tell which plug was installed before you replaced them? The other recommended part is the Denso SK20R11, replaced with the current Denso IK20.

I know the ones that i took out were NGK's. As far as the part # i think they were BKR6EIX11. Are they simply the wrong one's? I looked at NGK's site and noticed there are two types for my car. I dont think my car would stutter because of that would it? It just gets really annoying when i accelerate really slowly the popping noise is much more noticable.

[GuyTelefunken]

Easiest way to see is put the old ones back in.

[nuinqua]

Did you ever find the problem?