2004 Astro V6
This is the main reason I quit using local mechanics around my area.They seem to start with one part and continue to add/install more new parts until something eventually fixed the problem..then charged me for all the additional parts I really didn't need in the first place and the labor to put them in.This is definitely a tough situation, you have spent a lot of money with someone in good faith who has frivolously and quite randomly it seems, thrown parts at the van without ever addressing what is actually wrong with it. Now you are in a position where this mechanic will continue to justify all the random stuff he replaced as "necessary", and you quite reasonably must now question any work he did as well as the actual problem.
In the end,I started buying the books and doing my own work and learned a lot from that about what makes these cars tick/foul up, possibilities,etc.Yes..I've put in a lot of "Maybe" unnecessary parts..but overall my vehicles were high mileage and it didn't hurt,perhaps cutting off a possible future problem..but I never paid the 50% or more for the labor to have someone else guess at what would fix the problem.
I've had FORD dealers take out dash lights to not make the ":service" lights come on..service centers leave screwdrivers plugging old vacuum hoses("we fixed it"),a Washington Certified Emissions place fail my 8 cylinder van because they wrote in "4 cylinder" into their computer(cutting my emissions allowance X2);I noticed that AFTER a Certified Emissions Mechanic jacked my timing around on the van to pass the test and charged me the $500 for the fix..Just after the test,I took the van back and left it dieseling and loping along with the key off outside his office door while I stood in his office.He ran out and put it in gear to shut it off..right in front of some possibly(hope not!) new clients signing up for a repair.He readjusted my timing and said it was fixed again, already had my $500.
No..I'll do my own work..unless it is beyond my capabilities.I haven't seen an honest mechanic around here in a long time
Now my wife still uses one..and she has spent $1000s in unnecessary or faulty repairs,mechanics damaging her car,losing parts that fall off,or weren't put back on..If I can fix it..I will..I gave up telling her she should find someone else to work on it..I can't even get her to spend $15-20 on a repair book so i can see what it needs.
Anyway,listen to the people on here..they've been around the block working on these.There is a vast array of knowledge about these vans that you can't get elsewhere.