Idle problem

[deeps]

hi guys, my car is actually a toyota corona. It's the ST190, and has the 4sfe engine in it

It's very very similar to the 5sfe, so i'm posting it here.

I've had an idle problem for quiet a while now. The idle is not that bad, but it's still rough. It's idling a tad less than it should be idling, which is why it's rough.

So now during xmas hols i have a load of time to work out what's wrong with it.

So far i've done the following:

Plugs and leads - changed
Fuel and air filter - changed
Water Pump - changed
PCV - checked and cleaned - seemed ok, was shaking etc.
Coolant temp sensor - changed
vacuum lines - checked by spraying throttle body cleaner

Today, i'm going to try and buy a gasket for my throttle body onto the intake manifold, and remove the iacv, to check that.


I read the codes from the diagnostic box, and got code 22, which was my coolant temp switch. I checked that, and found it was melted and dead to buggery, so i changed that, and now that code is gone and hasn't re appeared.


The idle gets even worse when i turn the fan on (not a/c). Sometimes there's a weird 'tick tick' noise at idle, but it's not a lifter type tick, it's some other tick, which is hard to explain.


When i first start the engine, i get pinging/ticking as well, which seems to go away after ~2 or 3 mins.


What else could be wrong?!

[thousand_five]

What year?
ping/ticking may be oil. What oil weight do are you using?

[deeps]

it's a 1992 model

Not sure what oil it's got in it atm, it was last serviced by toyota about 500km's ago