2000 Chevy Blazer 2000 blazer starts..backfires..stalls whe

2000 CHEVROLET BLAZER
160,000 MILES • 6 CYL • 4WD • AUTOMATIC
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TWBBER
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My 2000 blazer.4.3l..was going down road and blazer started losing power. I pushed on the gas and it just bogged out, while losing speed and power..tried to feather the gas pedal but it eventually stalled..wouldnt start again. Went back later and started right up.. and was able to get it home.(barely) I quicly put gas pedal to floor and it just bogs and backfires. Went out later to start it, starts right up. When I give it gas..(while parked and driving) it backfires and has a chocking sound to the engine. I get the gas pedal qauter way to floor and it revs..anymore throttle and it does the afforementioned. When it get warm..about 5 minutes just idling..it stallls and will not start again for 30 min or so. It will idle fine.. and doesnt cut out or want to stall until it runs a few min...then stalls. Ive checked fuel pressure( which is fine) trouble shot the fuel relay cicuits(fine) changed plugs, cleaned and inspected rotor and cap,replaced plug wires, checked all fuses. Cleaned air filter.. replaced fuel relay..replaced fuel filter also.
Apr 28, 2010 at 1:51 PM
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TWBBER
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Ive donated, but no one answered this question. Maybe becuase I have 2 blazers..it was overlooked. Please help!!!!
Apr 29, 2010 at 9:41 AM
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TWBBER
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Been almost 24 hours now...no response..donated..?????
Apr 29, 2010 at 1:15 PM
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MERLIN2021
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First thing on OBD II vehicles, is to read the codes, Autozone does this free, but this sounds like either a weak fuel pump, or bad O2 sensor. 160,000 have you ever replaced the O2's?
Apr 29, 2010 at 1:38 PM
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TWBBER
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have ob11 scanner...no check engine light comes on. Checked for any codes..none. Never replaced o2 sensor. After blazer stalled out again today (after 10 min) I had a helper turn key forward as I layed under blazer to listen if the fuel pump was working.. Fuel pump was not coming on when I have them turn key to forward position without cranking it. Came back out 3 hours later, blazer starts right up. Thx
Apr 29, 2010 at 11:07 PM
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MERLIN2021
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Fuel pump will come on for 2-3 seconds when the key is turned to on, then stops unless the engine starts. Where your problem seems to be after the engine is warm? It's more likely to by an O2 sensor. Later on today I will get the specs for the fuel pump pressure, test that, test for spark, and because it does run, the compression should be OK. I think your pressure should be about 66 psi. But I'll check it this afternoon.
Apr 30, 2010 at 1:58 AM
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TWBBER
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After the blazer stalls from running..the fuel pump does not come on at all. Even when turning the key forward. Fuel pressure was fine when i checked it running....will only run for about 10 minutes..stalls..wont start again until it sits for awhile.
Apr 30, 2010 at 12:07 PM
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MERLIN2021
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OK There is a technical service bulletin about misfires, and the PCM ground strap on the head, some are at the driver's side rear of the head, some are at the passenger side head, remove the wires, clean all signs of rust and corrosion of both the wire and the head mounting surface, emory cloth works well, then re attach it, cover it with RTV sealant so it wont rust again.
Apr 30, 2010 at 1:17 PM
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GALLON77
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I have seen problems a with exhaust systems a number of times. A clogged catalytic converter will allow the engine to run at low rpm when cold. Once everything has warmed up the clog becomes more severe and will choke pout the engine completely. They is a tool designed to test pressure before and after the cat. I have seen cars go in and out of shops that could not diagnose this problem. The solution is a simple but somewhat expensive cat replacement. Sometimes an aftermarket cat will be available that is under $100. Usually these need to be welded in though. I hope this helps!
May 19, 2010 at 12:49 PM
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