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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29570
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I have a 96 silverado with vortec 350, it has a rough idle

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I have a 96 silverado with vortec 350, it has a rough idle that flucuates between 1000 and 600 rpm, along with this it has a serious hesitation and lurching at take off. code scan passes with no errors, have tried replacing MAF and IAC, changed spark plugs and checked for vacuum leaks around the intake and vacuum lines. What is advice can you give?
welcomeCustomer Have you tested the fuel pressure? Did you clean the bore for the Idle air control? Is the map sensor reading correctly? Try disconnecting it and see what happens. How does the truck run at speed? Let me know what you find.
Customer: replied 8 years ago.
I did not check the fuel pressure, however when I got the truck the fuel pump was bad, I removed the tank cleaned it out, blew out the fuel lines, then replaced the fuel filter and fuel pump. I did not clean the bore for the Idle air control. Honestly I have no Idea how to do that. I assume that the map sensor is working correctly, when I unplug it. the check engine light comes on and get a code for map input low.. The truck seems to run well down at speed, I have only driven the truck about 20 miles. During that drive with exception to the take off it runs well.
Ok. Check the fuel pressure. Unplug the MAP and try to drive it without it plugged in. Check the exhaust system for restrictions. Use a cleaner such as Sea foam. Follow the instructions on the product.
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