What’s up everyone, I have a 1987 deville, I’ve got an issue going on where my air filter housing is slipping apart, the lid is secured tightly. When cold starting, it runs great for about 15 min then as I accelerate and the engine warms up it begins to cough and sputter after 2k rpm and between 30-65ish mph, if I get up to speed it runs and shifts fine but the middle gears are giving me issues. The issue with the air filter housing is included in this, every time this has happened, the lid to my house has slipped off about 1/4-1/2 inch and is allowing more air than needed. Hopefully someone has encountered and solved this issue or can help me find new parts to replace the ones giving me issues.

Thanks in advance!!! Hope you all have a good one