CM871 fuel mileage

[Rawze]

Those 70+ mph speeds HAVE TO GO!.. learn to driver it 63~ish with better gearing and far less boost all the time.

What program does Insite say is in the ECM?.. and what is the engine ser# (the ESN#)?. Maybe a post pic of the data-plate if your not sure?

and what hard parts were installed during the inframe... that would be my next concern, as many places get the part#'s wrong and then your engine can suffer efficiency loss or other issues.

Also.. was the head re-worked?, or was a new OEM head installed?. Check the drivers side back corner near cylinder#6 .. If it is an RX or PX + part# and build date should be stamped into the head there.


will it pass a pressure test?...heck.. will the entire engine, intake, etc. pass a pressure test?. Anyone bother to pressurize the entire engine to 30 psi, front and back of turbo and check for any leaks?

Anyone did a second overhead valve adjustment 50k after the inframe?

Since fuel mileage is low, anyone bother to throw a set of wedges in it to see if one of the cams might have slipped?

A lot of unanswered questions there... and all related to fuel mileage.

- Those 386's (and 387's) are also prone to getting a fuel leak right over the exhaust or above the driveshaft and drip fuel while going down the roads, where no one can spot it without a trained eye .. Slowing down obviously will make lower fuel mileage if fuel its pouring onto the highways all day long. - Just another thing to add to the list of checks.