2RZ-FE maintenance ~160k

Hey, how's it going?

A family member's truck ('98) is starting to run a little rough while under operating temp, and close to normal when it's at temp. No DTCs. Is there any maintenance commonly needed around 160k on 2RZ-FE engines, or Toyota straight-4s in general, or just the usual things to check over?

As a point of reference, I know 1st gen Chevy small blocks. Not so good with the computerized components, but I can work on the mechanical parts.

Thanks.

 

Has the valve clearance ever been checked? Sometimes the valves on the 2rz and 3rz engines get a little tight. Fuel filter ever been changed? Start with the small stuff first.

 

Putting those next on the list. Thanks.

 

replace fuel filter, clean MAF sensor, clean throttle body, clean IAC valve, clean the EGR, replace plugs and wires, then, if all else fails, try replacing the injectors, for these engines its cheaper to replace them then having them serviced and you can upgrade to the newer more efficient style 4 hole injectors so it runs smoother.

look here: http://www.ebay.com/itm/271507095404?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

ps - they also all seam to have a cracked exhaust manifold right in the middle (remove the heat shield to see) so replace it with the factory steel header for the 2002-2004 2.7L engines