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1990 Cadillac Coupe Deville
1 Posts
Discussion Starter · #1 ·
New to the forum and looking to get some info and opinions on a problem I am having. I will give you guys a basic run down as detailed as possible and if I miss anything or you guys need anything let me know please.

1990 Cadillac Coupe Deville
Just hit 99k original miles

I bought the car from a 90yr old man he was original buyerMarch of 2019. He had it parkes for a good few months.
Soon as I purchased the car I did a full tune up, Ac Delco spark plugs, wires, cap, new belt, new tensioner, and coolant flush and oil change.
I’ve also let the car sit for around 9months just turning on occasionally.

Since I bought the car it had a heavy exhaust smell No smoke, and just a little loud and a slight misfire at idle, slight gas smell on drivers side when turning car off.

Never changed fuel filter.

Check engine light comes on and off for a e49 (air management system) but will go away from time to time.
I took the car to get a new cat converter and muffler and the guy told me it had a universal cat on there already and was in clear clean good shape.
So I then took it to get a compression test and one cylinder reads lower then the rest(#7):
Then changed the oxygen sensor.
I was then told it would be my fuel injectors causing the misfire. He then called me back and told me he doesn’t think the injector would cause a low compression reading that he believes its a valve leak.
I already ordered a diverter valve And check valves to take care of the e49 code. I’ve read that e49 codes will throw off a rough idle, rich exhaust smell, and oxygen sensor misreading.

So my question is can the e49 diverter valve cause the low compression reading also? And what should I look for as in my next step for the #7 cylinder reading? Any information would be helpful. Thanks in advance!
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