[Offroadadv]

Recently I purchased a 2006 Sequoia with 307k highway miles. I've replaced all the fluids, Timming kit, and spark plugs. I took out the plugs with an unknown how many miles on them. I was wondering if this forum could tell by the plugs the condition of the engine. Just for note when I bought it had and exhaust leak and a bad upstream of sensor. All the plugs looked the same. Here is pictures of the plugs. It now has 310k miles no noticeable oil usage and oil looks clean.

 

[jgrauman]

Looks likes it's been running lean. Probably because of the bad o2 sensor and exhaust leak. Put some new plugs in her.

 

[Offroadadv]

Looks likes it's been running lean. Probably because of the bad o2 sensor and exhaust leak. Put some new

I replaced the plugs, and PCV valve. Runs much smoother. Thanks.