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2005 Montana loss of power

Starcar33

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I have 2 Pontiac Montana's an 01 and an 05 the 05 has a problem when it's cold I can drive it and it runs great plenty of power but as soon as it's warmed up it has no pick up and go power tried a new filter no difference, tried putting in a new fuel pressure regulator no difference so changed the map sensor, throttle position sensor and the idle speed solenoid, new plugs nothing works, the only thing left is to replace the fuel pump! Any ideas?
 

melsg5

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Start with a fuel pressure test before throwing more parts at the problem.
Do you have a check engine light?
Look up how to test for a clogged catalytic converter.
Anything unusual about the gauge temperature reading?
 

melsg5

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What about the check engine light and temp gauge questions?
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when it warms up it switches fueling methods and the MAF/o2 sensors take over. do you smell a lot of fuel coming out of the tailpipe when this is happening? is the catalytic converter glowing hot when this happens? something in the MAF/o2/ecu systems is failing to fuel the car correctly OR something when it gets hot is failing. if you can at least narrow it down to one of those two scenarios, it'll help diagnosis greatly. your car should at least have stored codes, like melsg5 suggests, have the ECU scanned for stored/pending/current codes
 

Starcar33

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I replaced the top o2 sensor, don't smell any gas at the tail pipe I ordered a new diagnostic obdll one I can use a software on my phone or computer don't have it yet.
 
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I would suspect the rear o2 sensor possibly not keeping up with the new front one, but the scanner will tell you the final word on the problem. I'm going through chasing a lean code on mine. I've replaced my o2 sensors, fixed some air leaks, cleaned the MAF sensor, and still have a code.
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Starcar33

New member
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I would suspect the rear o2 sensor possibly not keeping up with the new front one, but the scanner will tell you the final word on the problem. I'm going through chasing a lean code on mine. I've replaced my o2 sensors, fixed some air leaks, cleaned the MAF sensor, and still have a code.
I ordered the sensor for my van I had to wait I'm on social security, I'll let you know what happens when I get it and put it in
 
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