HELP!!!! engine surges while in park

[adam9716]

I have a 1980 k5 with an 87 350 tbi. While the engine idles the rpms surge from high to low, and after the truck warms up it goes away. After I let it warm up and the surging stops I put it into reverse and the rpms go way down like its going to stall, but comes back by itself. When I press on the gas while in drive the rpms also go way down, and if i keep the pedal pressed it'll stall. I have changed the rotor, cap, fuel filter and spark plugs. What would be the most likely cause of this type of problem? fuel pump? Please help!!!

 

[StuGutz]

My 89 tbi 350 did the same thing and the egr was the culprit. was stuck in the open position. Could clean it (free it up) or just by new one. Hope this helps.

 

[adam9716]

My 89 tbi 350 did the same thing and the egr was the culprit. was stuck in the open position. Could clean it (free it up) or just by new one. Hope this helps.

Thanks for the reply, I did change the egr valve and it did not help. I ended up dropping the tank to put a new fuel pump in it and saw that the fuel sending unit was plugged up with rubber somehow. So I changed the sending unit and the pump, and now my truck runs perfect. Thanks again for the reply.

 

[StuGutz]

Thanks for the reply, I did change the egg valve and it did not help. I ended up dropping the tank to put a new fuel pump in it and saw that the fuel sending unit was plugged up with rubber somehow. So I changed the sending unit and the pump, and now my truck runs perfect. Thanks again for the reply.

NP glad ya got it figured out