Coolant, Manifold temp sensor and CPS all open?

My 89 was getting horrible mileage, rough idle, stumble off idle, etc.

New plugs, wires, cap, rotor, fuel filter, o2 sensor, cleaned throttle body, sea foamed it, set TPS, no dead spots found, etc.etc.

No change and getting 11 mpg. Has gotten over 20 before.

Checked manifold air temp sensor, open.
Checked crank sensor, open.
checked coolant temp sensor, open.

WTF. Hows this thing even run?

Voltage at MAP sensor seemed ok.

Inspect the plastic hose that runs from the MAP sensor down to the side of the throttle-body.

I was messing around bleeding air from the block at the coolant temp sensor and cracked mine in two. That gave me a horrible idle, seemed really rich (?) and my MPGs instantly dropped from -+ 20 to -+10. I spliced the hose with a short pc of vac line and everything was happy again.

5.0 Junkie said:

My 89 was getting horrible mileage, rough idle, stumble off idle, etc.

New plugs, wires, cap, rotor, fuel filter, o2 sensor, cleaned throttle body, sea foamed it, set TPS, no dead spots found, etc.etc.

No change and getting 11 mpg. Has gotten over 20 before.

Checked manifold air temp sensor, open.
Checked crank sensor, open.
checked coolant temp sensor, open.

WTF. Hows this thing even run?

Voltage at MAP sensor seemed ok.

Click to expand...

Sounds to me like you have the ohm meter on the wrong scale.... been there, done that

close. Meter is funked up. I checked again last night. Wouldn't work on 3 of the ohm scales. Kinda weird. Been using it for years with no problems. I replaced the IAT and CTS anyway. Still an off idle stumble. Going to replace the TPS anyway. MAP voltage seemed ok. Crank sensor was 227ohm, which I believe is ok. Have to see if the mileage changes. TPS voltage seemed correct through the scale, but right when you start to give it throttle starts loading up real bad.

Hose from MAP to TB is new. Been there done that.

Digger87xj said:

Sounds to me like you have the ohm meter on the wrong scale.... been there, done that

Click to expand...

for whatever reason my mileage decreases dramatically with the age of the motor oil...

change it and see what happens...