Re: Help!!! Changed spark plugs, Now rough idle (archive)

Check if you screwed them in tight enough. But dont overtighten either! You might have dropped some dirt inside the engine when you were replacing. Also check if all the spark plug wires are connected properly and firm enough. Disconnecting the battery cable for few minutes might help too. And check if new plugs are exactly for your type of engine. If not, you may notice some carbon build up on them or melted core part. If nothing helps get new set of regular Bosch and stay with them(?). I think they are just $2 each at carparts.com

'89 525

I changed the OEM Bosch spark plugs that had 60,000 miles on them with Bosch Platinum +4 (Part# 4417) plugs . Now the engine seems to idle rough. It does not seem to run as smooth as it did with the old spark plugs. When I started the car this morning the car sputtered and was rough starting. Normally the car starts up very smoothly and runs smooth after warm up. The car seems to also have a slight tapping as if a valve was tapping but it could be my imagination. The plugs where the same physical size and where easy to install. What might be the problem? was I given the wrong parts? Did i mess something up? Any and all help would be greatly appreciated.

Thank You
John W. List
1995 525 iA
166K miles

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