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94 GMC Sierra not running right, need help

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  #1  
Old 12-31-2013, 04:59 PM
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Default 94 GMC Sierra not running right, need help

I cant figure out whats wrong with my truck, I have to pump gas to start it, sometimes it idles bad, it spudders while driving, hesitates and rpms drop when i punch the gas stalls out when stoped, seems to be worse the colder it is outside. Ive changed fuel filter, spark plugs and wires, distributer cap and roter. any ideas I dont know what to do next.
 
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Old 12-31-2013, 08:36 PM
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Check for a vacuum leak at the base of your throttle body by spraying carburetor cleaner around the base. If the RPM changes when you spray the cleaner there, then you've got yourself a vacuum leak!

Have you checked your fuel pressure?
 
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Old 01-01-2014, 11:19 AM
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someone checked my vacuum for me and told me that there was no leak.
no i havent checked the fuel pressure.
And i forgot to mention when I bought the truck it was sitting for about 2 years
 
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Old 01-01-2014, 07:41 PM
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Have you put new gas in it yet and run it for a while?
TB may be plugged up from sitting and need cleaning/rebuilding
 
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Old 01-01-2014, 07:50 PM
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Yeah you could very likely have bad gas in there ... gas can go bad after just one year. Plugged fuel filter perhaps too.
 
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Old 01-01-2014, 08:08 PM
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Ive had it for about 6 months now, changed the fuel filter 2x.
Could the fuel pump get cloged up from sitting?
there were times the truck would run great, then all of a sudden back to crap again.
 
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Old 01-01-2014, 08:39 PM
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Yeah definitely check fuel pressure, also is your check engine light on at all?
 
  #8  
Old 01-01-2014, 08:53 PM
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It must be a fuel supply issue... If it won't start unless you pump the throttle? And it runs good periodically.... This could be a sign the fuel pump is on it's way out, or the fuel pickup is beginning to plug with slug or rust.
There is possibly a fuel filter under your truck on the frame rail and a smaller one at the throttle body.
Another possibility is the two injectors are beginning to clog
 
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Old 01-02-2014, 12:32 AM
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ya, the check engine light comes on randomly
 
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Old 01-02-2014, 04:10 AM
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Scanning the codes wouldnt hurt
 


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