Hey everyone I have a 1990 f150 xlt lariat. It has been running perfectly until a couple weeks ago. I did the check engine light test and the code I got was 45. From what I have read it is a air injection problem or the ignition coil. What should I start to check?

 

You can test your ignition components. easyautodiagnostics.com is a real good site for that.
What are your symptoms ? Does it run at all ? Poorly ? stall out ? Some details will help. Checking codes is the first thing to do, but because you have a problem and a code doesn't guarantee that the code item is causing the problem.

 

It does run. It idles a little rough. But while I'm driving it seems to have a skip sometimes and loosing some power.

 

Here is something you can try,check and see what the vacuum is at the soup can on the psgr fender,it should read around 20hgs at red line.Then check the black one that runs to the 3 solinoids,the reading should be same,If not,then the canister is rotted out[on bottom] or the line is leaking.If vacuum is good,then check the out line,coloured line for vacuum,the pink and yellow are running the air injection,it pumps air into heads and cat,if the lines are shot and they usually are,the valve wont open and can give you idle problems,the green one should be working as you have no egr codes. hope this helps,if all vacuum lines test out good,then you need to check solinoids..there should also be a vacuum schematic under hood,