When your ignition coil keeps burning out the cause is usually a bad ignition coil wire.
The wire that is on the middle part of your distributor cap and attaches to your ignition coil which is called the ignition coil wire is almost always the cause of premature ignition coil failure.
When your ignition coil spark wire is bad it causes the ignition coil to get too resistance which then heats the ignition coil up and burns out the primary and secondary windings in the ignition coil.
So if you have not replaced the ignition coil wire and spark plug wires then you should do so as that is what is likely causing your ignition coils to fail so quickly.
An ignition coil should last longer than a few months and you should get at least 10,000 to 30,000 miles or even 2 to 3 years out of an ignition coil.
I had this same problem with my 1992 Chevy Blazer which has the same engine and ignition coil and someone told me that I should change the spark plug wires and ignition coil wire and it should fix it.
I changed the spark plug wires and ignition coil wire out and my ignition coil no longer failed.
Bad spark plugs can also cause the ignition coil to fail so if you have not replaced the spark plugs in at least 50,000 miles then it would be a good idea to also replace those spark plugs.