When I bought my car last Feb , I checked the valve clearance and all of them were tight / closed and the car started up everytime like that and ran smooth like this, also with 223,000 miles on it . There is know record of anyone ever having them adjusted. So after I adjusted them it still ran the same . But the oil and filter were always changed on time , and most all of the normal maintance was carried out during its lifetime. Since I have had it I have gone over almost every little thing . I have 241,000 miles on it now and I will check them in a month or two just to see if they have changed, this way I can determine how long for the next time . I always change oil and filter every 4000 miles anyway.

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A couple of Ford pickups F 150,250, 350 missed.
1983 240 D 256,000 miles ,auto, ac.