Vacuum schematic
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Joined: Apr 2004
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Vacuum schematic
could anybody tell me where i can get a vacuum hose schematic for a 1989 F250? i'm not sure if these can be purchased anywhere or not. i am having rough idle/missing problems with my 351 engine. codes showed a 22, so i changed the map sensor. didn't do a bit of good. advance auto parts ran a stored code check and found the oxygen sensor was bad, but nope, that did no good either. the engine was tuned last week, including plug wires, dist cap and rotor. i put a new IAC on it, and am still having the same problem. i've just about figured that the vacuum hoses might be hooked up wrong. i just bought this truck 3 weeks ago, so i do not know the history. am open for suggestions...thanks...ed
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Joined: May 2002
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From: Fraziers Bottom, WV
Ford puts a tag under the hood of the truck with the hose routing. If this is missing, you will need the "calibrations code" from another tag on the engine and Ford can provide the hose routing.
A map code can come from just about any other sensor, relay, vacuum valve or bad wire on the truck and the map not be bad. I would warm the engine and do a compression test on all cylinders. One bad cylinder can cause poor idle/miss and cause the codes you described. If a good scan tool is used you will get an error "unable to control engine idle". This is another good sign of a bad cylinder. I would look at the drivers side back cylinder first. For some reason that is the most common (that I find).
A map code can come from just about any other sensor, relay, vacuum valve or bad wire on the truck and the map not be bad. I would warm the engine and do a compression test on all cylinders. One bad cylinder can cause poor idle/miss and cause the codes you described. If a good scan tool is used you will get an error "unable to control engine idle". This is another good sign of a bad cylinder. I would look at the drivers side back cylinder first. For some reason that is the most common (that I find).
