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Dear Master Auto Tech, I own a 1995 Chevy Blazer 4.3L 4wd with 200k plus miles. It runs great, lousy fuel mileage. The problem I am writing about is the truck won’t start when cold. I changed fuel filter that helped for a while, but the problem came back. I changed filter again, no help. Fuel pump works (can hear relay click), idle air solenoid good. Now the only way it will start, hot or cold is to prime it with a squirt of gas to the throttle body. Once it starts, it runs great, but don't turn it off 'till you get where you're going. I have not performed any other diagnostics. I am a poor man. Where do I start to look for this problem? Charles E. Panama City

Charles I can guess what your problem is and I may be 100% correct, or I may be 100% wrong. In my experience over the last 40 years I have run across this before. In just about every case, it was the fuel pump not having enough pressure to help “pop” the injectors when the car engine is cold. The correct fuel pressure is 60 PSI. If you have 55 psi from the fuel pump it will not start without assistance (squirting fuel down the throttle body, cold or hot.) This low fuel pressure will affect your fuel mileage as well. I am going to suggest that you find a shop that will confirm your fuel pump pressure is not correct. This needs to be the first thing you do BEFORE you change your fuel pump and spend money you don’t need to spend. Live long and prosper in 2012! James Morris

 

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