Sparkynz

Wanted to give a little update in case anyone in future encounters this post: Spark plugs helped, but rough running returned (vehicle wasn't used much over winter, so it didn't manifest for a while). It was indeed the head gasket (just minus many of the telltale indicators until it was in bad shape!). Really appreciate all those that offered advice, and hope this helps the next person.

Good to know! New set of plugs on the way, starting there - fingers crossed!

Thanks for the reply - oil & cap look healthy (luckily!)

Hello engine brains trust! A friend suggested I post here to get an idea of what fault-finding direction to go in, as someone else may have had a similar issue. Any help would be so appreciated before I go pulling all sorts of bits off to even get to the engine. 1996 Toyota Estima, 2.4l supercharged, auto. 350,000 odd kms on the clock. Generally runs beautifully, never misses a beat, well-serviced history. Recently has been running rough on start-up, from 10-20 seconds up to a minute or so max, then smooths out. Generally doesn't happen on hot-starts, sometimes on 'warm-starts', and never once running. The sound is rough/lumpy/uneven rather than a 'popping' or backfiring. More like its only firing on 3 cylinders perhaps? Seems un-related to weather or temperature. Any leads on the direction to go re what may be causing it would be great, it's a tricky wee thing to get access to! Thanks in advance, -