slightly rough idle after changing plugs

[hazydream999]

hello everybody.

I ran into some problems when changing out my spark plugs on my 06 ex. i somehow stripped two of the holes and had to helicoil both of them. I now get a slightly rough idle after driven for about 15-20 mins. after the ex warms up it then stops. any clue as to what could be causing it? I used autolite platinum plugs i believe

 

[Cobraguy]

Well, I am a firm believer in using the factory plug. So I have no idea if it could be plug related or not. You have a lot of variables here to double check. Did metal fall into the combustion chamber from your helicoil process and do some damage? Did you crack a plug? Are all wires properly fastened? Are the plugs grounding properly through the helicoil? You could do a visual inspection, and check compression. Any more than that, you may have to have it looked at by a shop with expensive diagnostic equipment. Ohh...are you getting a CEL and code? That might tell you what cylinder is missing.

 

[conig]

some cars hate platinuim plugs ive had what was a miss from blow out on platinuim plugs i never use them anymore. just ngk coppers.

 

[Dre]

two things: one - you might be loosing some compression because of the helicoils - make sure they're tight; two - did you make sure to put the wires back where they belong?

good luck!

 

[rumpledoll]

What happens when the engine warms up:

1) Aluminum head expands to grip the steel based plugs tighter. This is why you need to wait for the engine to cool before changing the plugs. All materials expand and different materials expand at different rates.

2) The engine runs leaner as the PCM goes into closed loop management mode.

My guess Dre nailed it - compression leak until engine heats up. Suppose it could also be loose wires making a better connection after it heats up.

FWIW I'm running Champion Double Platinum plugs in my 2002 V6 4.0L and it purrs.

Rumple

...after the ex warms up it then stops. any clue as to what could be causing it? I used autolite platinum plugs i believe

 

[Dre]

plugs... we always talk so much about plugs... I have installed Bosch Platinum plus4 in my 94 Un-Limited about 8 years ago... plugs and Bosch wires... so far no problems at all and almost 100,000 miles on the odo since.

I'm afraid to do it to my 02 Sport since everyone complains so much about Bosch and it's time to replace wires for sure.. I even thought about just installing NGK plugs and put stock wires back on... just new.

Anyway - yours is like brand new... should not give you any trouble and since all the trouble started as soon as you replaced plugs that's where I would look for a problem.

 

[Cobraguy]

If it were leaking enough compression past the helicoil to miss, you would hear it. No doubt. Check for cracked plugs, proper wire routing, etc as suggested.