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Username Post: Need repair help!!!        (Topic#344006)
Forum Newbie
Posts: 2

Reg: 04-13-17
04-13-17 06:35 AM - Post#2686436    

Hey to anyone that can help my truck has been giving me fits since I bought it. It's a 1992 k1500 5.7. The story of the truck is the last owner ran it hot so he rebuild the motor. It has original block and newer vortec heads with a jegs intake. The problem I'm having is when rough idling and it's bogs down bad when accelerating when you hit the gas the rpms will drop and sometimes backfire. I took it to a shop and they replaced fuel pump, new plugs and wires and a computer he got from a junk yard nothing help so I got the truck and I put in a all new distributor from O'Reillys rebuild the tbi new map sensor new iac and I tested the tps and it tested good so I don't know where to go from here I hope someone can give me some insight on this... thanks


Very Senior Member
Posts: 4143

Reg: 12-29-02
04-13-17 08:53 AM - Post#2686450    
    In response to Ryanb

You need to tune the EFI to match the engine modifications.

Go to to get the equipment and to get help on how to do it. The best is to use an APU1 and the adapter necessary to connect it to your ECU. Then, you can make changes real-time while the engine is running. It seems like a lot, but it's not that difficult once you get started.

Alternatively, you can go to and get a conversion for your ECU that allows you to flash it.

You could also ask if anyone is willing to help for a fee. I think there's at least one user that might do it, but you'd likely still need the working APU1 installed so he can tune it remotely.

It's also likely you will have to replace the fuel pump with a higher pressure unit (TPI pump) and then modify the stock fuel pressure regulator to increase the fuel pressure 5 to 10psi. The reason is that the stock pump and injectors likely aren't capable of supporting the extra power the Vortec heads will make. Increasing the pressure is similar to installing larger injectors.

Forum Newbie
Posts: 2

Reg: 04-13-17
04-13-17 06:47 PM - Post#2686527    
    In response to 65_Impala

That might be out of my league is there a after market computer or a chip I can buy?

I did not know you would have to do all of that when I bought the truck. I may just end up putting same year heads back on it


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