I know there are a bunch of threads on this issue, but this one is different. I put in a used motor with 60,000 miles on it out of a 2003 ranger and ever since install I get a rattle on most start ups for about 10-20 seconds. A light clack can be heard while idling sometimes. My gas mileage is terrible, about 6 city 9 highway. Truck runs fantastic is the strange part. No check engine lights and fuel trims are perfect. I'm thinking the tensioners are bad which is causing the timing chain to be loose and throw off the timing a little which is creating my terrible gas mileage. Can anyone chime in and tell me if I might be right? If that is the case what does it cost to replace the tensioners? I know the guides are good I saw them when we put the engine in.

 

Timing chain service requires engine removal for the rear unit. You didn't replace all that stuff when you put it in the truck?

Your fuel economy problems probably have their root elsewhere. No lights, but have you tried to pull codes anyway? You might be stuck in the cold start mode or something like that.

My worst mpg was 11 short city driving, and I actually hit 20 once, but usually got 15.5 in mixed commuter driving. 16 one time when I took it easy...

That it runs good but still eats gas is a bit of a mystery....I would expect some black smoke or a bog somewhere if it's running so rich.

Mine rattled pretty good on start up BTW, long before it's 101,000 miles at the time of it's demise.

 

Put a scan tool on it many times. No codes. Nothing pending truck is perfect. No rich running smell, no bogging, now loss in power, no issues pulling a trailer, transmission shifts perfect(rebuilt 15,000 miles ago). I just don't get it. Everything on the truck is new or rebuilt.

As for the chain service while engine was out, didnt think about it. Figured a motor with 60,000 miles on it should be perfect. Why would there be timing chain issues. The motor that came out had 149,000 miles on it and still ran but sounded like a marching band was inside. Bought the truck from a young kid who never heard of maintence before. He didnt change the oil for 30,000 miles. And that's why it blew.

 

Well decided to take it to a shop and let them figure it out as soon as it gets out the upholstery shop.

 

Your MPG numbers are head scratchers....maybe the shop will find a smoking gun..... It just makes no sense that it runs that good but uses that much fuel. Other than a leak or someone stealing gas, how could it be....