I have 99 SEAT Ibiza, which was until quite recently owned and driven by my mother. It's therefore been well cared for, but was hardly ever given a good run or allowed to get warm. On its last major service - which was early this year - the oil was a suspicious colour which the guy said can warn of head gasket failure, but given the treatment it's had, he figured it was more likely to just be residual moisture that hadn't been given a chance to cook off.
Anyway, for a few weeks I've been noticing a light tinkling sound coming from the engine bay when accelerating. I change gear early for reasons of economy, and being a fairly new driver I don't always time it right and the engine can struggle under load. The noise is most noticeable changing from 3rd to 4th at around 2000rpm then applying some firm throttle.
From the information I have and what I've read, I suspect engine knocking or misfiring. Detonation due to dirty plugs would fit the treatment it's had previously - short runs would tend to cause crud buildup, or so I gather. A friend has offered to help me inspect the distributor cap and spark plugs, but is there anything else I need to be aware of or look for?
Thanks folks. Taking advice, I've gotten into the habit of leaving the gear change til later - usually 2.5 to 3k, and the problem has pretty much disappeared.
I've also taken to giving it a blast up to 5k RPM when joining the highway each morning to clear away the cobwebs...but we won't tell anyone about that, will we?