Engine rpm drops low after startup

For about a week now my truck is starting up funny. Right when I crank and fire it up, it bogs down like it's going to die then slowly comes back to a normal idle. I looked at my vacuum lines and everything else looked good in the engine bay. I put the upgraded walboro fuel pump in about 3000 miles ago, could this be going bad? Anyone else have this issue or a reason for this?

 

I would look at your intake air temp and coolant temp sensors. They are usually the culprits. If it indicates the engine is warm, when it isn't, it will use the warm engine fuel mix and idle settings.
You can test them with hot and cold water and an ohm meter. The resistance should change from one to the other. Only immerse the sensor end.

 

try cleaning the throttle body

 

To the OP. Wondering if you figured out the problem? I have a similar problem only during a cold start. Will be cleaning the throttle body soon to try and fix.

 

I tried cleaning the throttle body and the MAF. I still have the same problem as the OP. Will be trying some Seafoam on my next fill up to see if that fixes anything.

Skytower: can you tell me a little more on how to check that? Even when starting my car from my garage, which usually sits around 50F in the winter, I still get similar results. Thanks

 

Please. Don't use seafoam.

 

Why? I live in Colorado and with ethenol in our gas thought it may help?