Okay, I've searched around and can't seem to find a definite solution to this so I'm gonna explain it here.

This just started happening a month or so ago, but when my car has sat for a good amount of time (overnight, few hours or more) I get this ticking/rattling sound at start-up. When the car is at idle you can't really hear it but when you rev it or put the engine under load is when the sound becomes more noticable, but the sound will go away after a few seconds. Then as I shift into second gear and the engine comes under inital load again, the sound returns but is only loud for a few seconds then becomes slight. After about 10 minutes of driving the sound goes away completly and all I hear is the normal ticking of the valves and injectors. The sound itself seems to be coming from what I believe is the #4 cylinder (closest to the distributor). And when under the hood and reving the engine it almost sounds like something rattling in the head, but performance wise the car drives fine. The only thing that I experience is when the engine is cold my revs are very low (around 600) until the engine warms up, then the revs will hold steady at 950-1000.

Like I said the car used to not do this and only has for about a month or so. Someone has mentioned to me about putting in a slightly thicker oil to see if that works but other then that I have no clue what this is exactly and I'm hoping for yalls help. Thanks.

 

make sure oil level is good is the first thing i would do.

Secondly if its coming from inside the engine, then i would do a compression test/leakdown just for the heck of it.

When was the last time your valves were adjusted?

 

I would second the notion on adjusting the valves.

I would do that asap and then if it stops itm its all good, but I'd do a leakdown/compression check to for ***** and giggles.

 

The last time the valves were adjusted was a couple weeks ago, it also had a 120,000 mile service done to it as well. The oil level checked out ok today.

 

compression and leak down?

Also your belts are next to your 4th cylinder. Maybe check the belts or play in any of the pulleys. You could always open the valve cover and look around. i dont know.

 

Check your idler tensioner pulley, they have a tendency to go bad around your mileage. Mine is going, i thought it was my valves, adjusted them, still makes the noise. Mine makes a slight rattling at idle or when i'm coasting off the gas. A shop wanted 250 total to fix it, I'm just going to leave it be since I should be throwing a B18c in anyway.

 

If the #4 cylinder is near the belts then the sound is coming from around the #1 cylinder, sorry for the confusion.

 

has the problem been solved yet ? i'm also getting the same symtoms as you....