87 golf 1.8 no power warms up runs good

I have a 1987 Golf 1.8 Car had been sitting inside for 4 years and trying to get it running good.I have drained the tank,Installed a new outer fuel pump,Pump in tank is fine,replaced fuel filter,rebuilt fuel distributer,fuel pump relay and new plugs.When you first start the car it runs very poorly and you can put the pedal to the floor and the engine just sounds doggy no power.After the vehicle warms up about 5 minutes it seems to run real good.Shut the vehicle off and restart it after 3-4 minutes its doggy again and no power again until it warms up again about 5 minutes.We found that a mouse had stored corn in both of the mufflers so we cut those off and we will install new ones.That didnt make a difference how it is running.Any ideas on what might be the problem and if you have ran into this before?Thanks for your time!

This car runs it just has no power and very doggy.Can only get the car up to 45 mph.Are there any VW guys out there that can suggest something please to check ? Thanks for your help!

Thanks for all your help not! Ha ha! Car is fixed and runs perfect! It only just needed a muffler belt! You lug nuts!