I need help fellows.. Motor losing power.

[Supreme70]

I have a 87 truck with a 350 Throttle body injection unit on it and the problem I am having is it will run fine when first started but after alittle while it starts to bog down and lose power unless I floor it then it runs fine. If I shut it off and restart it it runs fine and then it will start losing power again. I have a feeling its the T.P.I. unit but would like some more opions as what you think it is. It is also the worse when it rains or snows. when dry I dont have the problem.

 

[Chevy305]

could be moisture in the iginition system?

 

[Pvt. Maggot]

What exactly is the motor doing, bogging, cutting out? Could be water in the distributor, need new plugs and wires, clogged fuel filter, ect.

 

[Supreme70]

What exactly is the motor doing, bogging, cutting out? Could be water in the distributor, need new plugs and wires, clogged fuel filter, ect.

When I first start the truck up it idles fine and runs fine for about 5 minutes and then it starts bogging and it almost stalls then it will surge and and then start to bog again, if I go to full throttle it runs great until i let off then it acts funny again. I have done a full tune up on it and its still the same, it happens when its wet or snowy out but once its nice it runs fine. Im hoping its just the throttle position sensor. but want second opinion.

 

[Cowboy_80]

I think maggot was right. water in the distributor. If it runs fine when the weather is good, but not when it's wet out, there must be moisture getting somewhere. Distributors are notorious for this. the TPS should NOT be affected by weather.

*edit because I'm illiterate.

 

[Pvt. Maggot]

Check the plug wires, make sure they are tight. Run a bead of silicone around the edge of the distributor. rule those out first, then let us know.