97 land cruiser runs rough with cold weather

[ccslider]

My truck is acting weird, only when the weather is cold, not the engine cold but the ambient temperature. I drove it to arvada this morning from broomfield and it was acting up during hard throttle. I just drove it at lunch and its running fantastic.

When it hits 3k rpm at full throttle it will act like its being starved for fuel. Bucking, hesitation. Light throttle it will accelerate fine. Neutral revs fine. My truck is Supercharged, has good vac at idle -15 / -20 or so.

I ordered a fuel pressure tester but it wont be here until Saturday.

Stuff i've done / checked.
changed the plugs NGK copper 4844 colder for supercharger, old ones looked carbon fouled
replaced cap / rotor, had some wear
replaced wires, 2 were close to being out of resistance spec
oem fuel filter
Checked the harness by egr, I had previously wrapped it / secured away from tube.
Checked timing with light
no codes
TPS is showing proper range on scan gauge of 12-88%
Idle is perfect
Newer o2 sensors
checked for vac leaks
did the wiggle test on wires and connectors
head gasket was done 25k ago


I was thinking maybe an injector is sticking, at idle i could hear each one firing. Im trying to think of something that is shrinking with the cold but I'm drawing blanks here.

land cruiser miss

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[60wag]

How old is the intake hose between the MAF and the throttle body. It may have a small crack in it.

 

[ccslider]

How old is the intake hose between the MAF and the throttle body. It may have a small crack in it.

Supercharged doesn't have that rubber hose, it does have rubber couplers in a few spots that are older

 

[White Stripe]

During hard throttle the ecu should rely on the maf only. Is your maf clean? On another note your tps should go to 100% I would think, not just 88. Is your throttle cable adjusted right? You could be leaving power on the table if not.

 

[ccslider]

During hard throttle the ecu should rely on the maf only. Is your maf clean? On another note your tps should go to 100% I would think, not just 88. Is your throttle cable adjusted right? You could be leaving power on the table if not.

I thought that too but I found out it's normal to show 12 at closed position and 88 at wot, I tested by manually operating butterfly.

Truck has been for running great. I wonder if I had bad gas.

 

[IoN6]

3k RPM is when the Fuel Pressure kicks up. The test is easy to do, just time consuming to setup (at least how I did it...). Need to remove the 2nd row, pop the fuel pump access cover, de-pin the male connector to the fuel pump and then you can put a volt meter on it. Go for a drive, IIRC should be ~8v at idle and up to 3000 RPM. At start up and >3000 RPM it should kick up to >12v.

I would also check your MAF for the temp readout. I had a similar problem (although totally opposite, ran fine in cold / crappy in heat), and I think it was related to the temp sensor in my VAF. Everything else tested fine, but once I swapped she's ran like a champ for over a year now.