that is a good motor it does reasonably well on gas milage as well. 141,000 miles for $4500 is a good deal. book price on that vehicle for that many miles and in fair condition is around $8,000. as long as their isn't any bad leaks or body damage i would buy the van. but it might be a good idea to get some sort of a maintance record that has been performed on the van because people tend to abuse those sort of vans. But as long as the maintance has been kept up thats an excellent buy.
I have seen the 4.6L (which is what the van should have in it i have seen a 4.8L in a van before) get as many miles out of it as the 4.3L, under the conditions that both engines were properly maintained. any engine will get that sort of milage as long as its maitained.
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ASE Certified Technician
Have 6 years experience and am a ase master auto tech& i have recently started working on heavy eq.