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Discussion Starter #1 (Edited)
on my 92 blazer 4.3 CPI i have had a full tune-up on it, changed wires,plugs,coil,distributor,fuel filter,air filter, and i have ran numerous amounts of fuel treatment/injector cleaner thou it. it has 215,000 on it and the lady i bought it from let it sit in the backyard for 2 years. the problem I'm having is it has a rough idle shakes the interior etc, and a popping from the exhaust pipe, also if you let it set and idle for to long when you take off his has a hesitation to it but having flouring the gas pedal it clears up and takes off.

can anyone tell me what might be wrong?
 

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Discussion Starter #2
1 last thing i was getting a code 45 would an o2 sensor be causing all these problems?
 

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Clean N' Dark
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Could be a faulty O2 sensor.

I think your CPI might be shot.
 

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Discussion Starter #5
spark plugs are all right. how much its the cpi and where can i buy it online and how hard is it to replace
 
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it could still be your O2 sensor, Code 45 is a Rich O2 reading, so its obvious the computer is dumping in lots of fuel cause the computer doesnt understand what the hell is going on.

Sensors are about $45 which is going to be a lot cheaper than a CPI unit. If you have a friend in the area with 90-93 S-Series 4.3L, try swapping sensors and see if that does it before blowing $45. I think it requires a 7/8" wrench.
 

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FactorY RolliN
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mine does that tooo it sat for a couple of months out in the weather... but i havent tuned it up yet it only has 108k still starts good and runs good though just idles hard
 

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Kramerica Industries
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342 Posts
Take your plenum off and look at the CPI unit, if one side looks 'clean' that usually indicates a fuel leak on that side.

A leaky CPI could cause all the symptoms you are describing, and would be putting so much gas into the engine the O2 would probably get a rich reading.
 
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