problems running right

[therover87]

i have an 87 k5 350 tbi and when i start it up in the morning it runs mint, idles great and it smooth after 5 minutes the idle will jump all over the place and it will be surging i have replaced the fuel pump, fuel filter, strainer, plugs, cap, rotor, wires, coil, egr valve, o2 sensor, pcv valve, if someone could help with me it would be appreciated, thanks.

 

[abusedtrucks]

Take it to a shop.

hehe...

 

[Can Can]

Jeez, does anybody have any ideas??? It sounds like the brother has replaced all the parts that could cause this problem.......

I'd be curious to hear what others say because my brother-in-law's 91 is doing something similar.

 

[BrianDamage]

have you used a code checker to check the codes?

 

[YtseJam]

Does the Service Engine Soon light come on? Are you getting an EST error code? Did you check for DTC'S? It loses power after it gets hot, Is the Catalytic converter restricted?

 

[YtseJam]

Also check for a vacuum leak @ the base of the Throttle body. Spray carb clean at the base of the TBI and see if the idle changes, The base gaskets get sucked in and cause a large vac leak, the IAC tries to compensate.

 

[Haulgas]

I had the samething on my 87 it was the water temp sensor
Try that.