Ticking sound on 3rz Hilux 98 model 2.7lt petrol

[wassaby69]

Hey guys I have tried searching this but could not find much. I have a ticking sound on my hilux 2.7 lt petrol. Im pretty sure its not the exhaust as i have had a good feel, look and listen around the exhaust manifold while someone had there foot on the end of the exhaust.

The ticking sound is not there all the time only when i put load on the car like overtaking and climbing hills. It seems to be lacking in accerlaration too really have to put the foot down to get any where. Was wondering if any one could help on where to start. was going to change spark plugs, oil and filter and try running some subaru upper head cleaner through the car to see if it makes a difference. Car has 229,000ks on it. Any advise would help a lot.

Thanks Bj