96 350 vortec back firing and loss of power

Asked by Dec 26, 2014 at 02:26 PM about the 1996 Chevrolet C/K 1500 Cheyenne Standard Cab SB

Question type: Maintenance & Repair

i have a 96 chevy 350 vortec. just changed the motor in it and cant get it to run right..it will
sit there and idle great when its it park...when i get out on the road it starts to loose power   
and back firing alot but only when i get to about 25-30 mph. help me under stand this.
took it to a shop they said i had a air leak in the intake,now there saying that  valves are
too tight...what is the problem?  you can email me at dustinjboshell@gmail.com...

5 Answers

66,125

Is it running hot as well? If so it's going to be a knock sensor problem. Sounds like the knock sensor is retarding the ignition timing. HTH. -Jim

no its not running hot at all... like i said i just bearly replace the motor with a long block from city motor supply in dallas tx...so its been at the shop for a week no and they keep telling me that its this and that but when the replace that part and put it back together its the same way as when i drop it off to them..... just trying to get some answers to why its doing this.... i read also about the cam retard offset... wouldnt that give them false codes if that was not set right???

66,125

It could give false codes but not necessarily. If the computer thinks that the engine is pinging it will retard the ignition timing. I had that happen to me on my '93 Caprice when it got old and develop a valve tap. HTH. -Jim

1 of 1 people found this helpful.

So your saying that it's the kn ock sensor.

66,125

It could very well be. The knock sensor is like a microphone. It "listens" for the engine pinging and retards the ignition timing until the pinging stops. If you have other noises going on near the knock sensor it may pick them up. On my Caprice the valve tap was right next to the knock sensor. With extremely retarded ignition or valve timing you'll get loss of power, popping back at the intake/throttle body, late transmission shifting (older models), and heat soaking. HTH -Jim

3 of 3 people found this helpful.

Your Answer

Add photo

Related Questions

  • 96 Chevy C1500 5.7L Vortec Truck won't start, Replaced Fuel Pump, Filter & Has Spark. 81 answers

    Hey everyone, I have a 1996 Chevy C1500 with a 5.7L Vortec, I got the truck recently and was told it just needed a Fuel pump, I replaced the Fuel pump, and the Filter, also the pump turns on and there...

    Chevrolet C/K 1500

    -

    Maintenance & Repair

  • Loss of power, battery draining leading up to severe miss firing and back fire 2 answers

    Problem came on suddenly. I made no changes or additions to the truck. Then the voltage needle dropped from center at about 14 to less than half that. Had the battery/alternator checked they said th...

    1993 Chevrolet C/K 1500 Indy Pace Standard Cab SB

    -

    Maintenance & Repair

  • No low end power 31 answers

    I have a '97 k1500 with a 350 and 4l60e automatic. Assuming all things are OK with the truck, would a bad fuel pressure regulator cause it to have no power at low rpm's? It always bogs under acceler...

    1997 Chevrolet C/K 1500

    -

    Maintenance & Repair

  • No fire on this 350 sbc

    Ok I just bought this k1500 they started to rebuild it and I put it all back together besides relashing the valves but got tight enough to start it but it won't start. I think once when I hooked a...

    1988 Chevrolet C/K 1500 Cheyenne Standard Cab SB 4WD

    -

    Maintenance & Repair

  • How Do I Know What Engine Is In My Truck? 51 answers

    So I just traded my 1998 Dodge Dakota Sport for a 1998 Chevy Cheyenne 1500 4x4. The kid I got it from said it had a 305 from the factory but somewhere down the road a 350 replaced the 305. My questio...

    1998 Chevrolet C/K 1500 Cheyenne Extended Cab SB

    -

    General

C/K 1500

Looking for a Used C/K 1500 in your area?

CarGurus has 892 nationwide C/K 1500 listings starting at $2,500.

ZIP:

Search Chevrolet C/K 1500 Questions

Chevrolet C/K 1500 Experts

#1 Andrew Olsen
Andrew Olsen
Reputation 3,340
#2 John Saffrahn
John Saffrahn
Reputation 2,500
#3 Rowefast
Rowefast
Reputation 2,050
View All

Related Models For Sale

Used GMC Sierra 1500
825 Great Deals out of 68,199 listings starting at $2,484
Used Ford F-150
2,195 Great Deals out of 206,316 listings starting at $1,499
Used Chevrolet C/K 2500
214 listings starting at $2,250
Used Dodge Ram 1500
453 Great Deals out of 11,152 listings starting at $700
Used Chevrolet Tahoe
549 Great Deals out of 29,234 listings starting at $1,699
Used Chevrolet C/K 3500
237 listings starting at $4,995
Used Chevrolet Camaro
226 Great Deals out of 30,943 listings starting at $1,217
Used Toyota Tacoma
542 Great Deals out of 40,814 listings starting at $2,495
Used Chevrolet S-10
10 Great Deals out of 1,345 listings starting at $1,395

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.