You can change just the one lifter, however you should determine why it went bad. The intake manifold must come off to get to the lifter. Is there advanced mileage? do you change the oil regularly? Seeing how it is an 87 vehicle, with 19 years of use on the engine, I would strongly suggest changing the full set. Be carefull though as there is the possibility on that engine of 2 different size lifter bores. If yours are oversized it will be stamped on the lifter bore (not on the lifter) 0.25mm 0.5 There should also be a white paint mark at the bore.
remove intake manifold.
jaguar 2001 Lower Engine Intake Manifold Gasket
Pretty straight forward. You must remove the intake manifold in order to replace the gasket.
diferential pressure sensor intake manifold plausibility
Remove the intake manifold retaining bolts on your 2003 Chevrolet Malibu. The manifold will come off. Remove the manifold gasket and clean the surface. Put the new manifold gasket on and reverse the process.
Yes, change both of them.
What engine? and ensure it is a bad gasket, not an intake plentum.
No absolutely not...
take it to a mechanic
you have to remve the intake manifold