Bucks in cold weather.

[RochesterXLS]

I have a 2000 XLS 5 speed with 123,00k that intermittently bucks or hesitates in cold weather, never when it's warm. Not reproducible easily and no codes show up as I have had it serviced for faulty EGR. Have recently changed air/fuel filters, new plugs at 100,000. Plug wires seem in good condition. I don't worry about being stranded, just annoying.

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the stock 95-01 section. Replace the fuel filter, and use fuel injector cleaner. Clean the mass air flow sensor, throttle body, and intake manifold.

 

[2000StreetRod]

ECT sensor

The PCM decreases mixture richness as the engine warms up using information from the engine coolant temperature (ECT) sensor. If the ECT sensor is inaccurate the mixture will be incorrect. Easy to test with a scanner. A little more difficult using an ohmmeter for the SOHC V6 due to accessibility.

 

[RochesterXLS]

Thanks guys. Fuel filter is new and nothing different since last winter. I have cleaned MAF sensor with no changes. I'll try other things. Would a code for the ECT sensor show up as it's only an intermittent issue? I've had it scanned in the past with nothing showing up. I'll try and see what happens. Thanks for the info.

 

[2000StreetRod]

ECT sensor code

The only time the PCM will set a DTC due to the ECT sensor is when it is shorted or open. Anything in between those values could be valid.

Another possibility is leaking intake gaskets resulting in a lean mixture. It can occur on both the OHV and the SOHC but happens more often on the SOHC. If the leak gets bad enough P0174 and P0171 DTCs will get set.