GMC Idles only

[WI_Dave]

I have an old style 99 GMC 2500 4x4 5.7 w/powerdyne supercharger no tune.

Two seperate times in the last 2 years truck will start and idle fine but if you give it gas it will start to rev then die. I tried disconnecting batt. checked fuel press.

after several tries restarting and trying to drive it it just started working normal again. What could cause this? Only thing I can think of is knock sensor.

 

Any help will be greatly appreciated, Dave

[GM-Tech]

Never seen a knock sensor cause anything like that and I don't believe it could. As to what it is... ya got me. What's the MAF doing when this happens? How about TPS? What are the fuel trims when it happens?

[WI_Dave]

No check engine light, fuel 50psi to 60psi, how do I check what MAF and TPS are doing?

 

I thought knock sensor shut off spark if ping detected.

[GM-Tech]

No, it doesn't shut off spark, it only retards it until it doesn't see any knock. You'd need a scanner capable of viewing those data items.

[WI_Dave]

Thanks for the help. Now I might have to wait another year for it to happen again

so I can scan it.

[WI_Dave]

It happened again and this time I figured it out. The stock fuel pump

stopped working but the in-line from supercharger didn't the in line one

couldn't get enough gas to motor by itself.

 

 

Edit: I don't know why my pressure gauge read wrong maybe its junk