Valvoline Restore and Protect in a car with leaking valve seats

[2000fordfocus]

Ignition coils bad? Try to throw some parts at it and continue to run this Restore oil. You've not done anything wrong though.

i replaced the ignition coil pack, plugs and wires in june(?) 2023. it was diagnosed with low compression in cylinder 4 by two different shops, first in october 2023, then again in december 2023. the first one said it was because of leaking valve seats. i should still test the compression myself but i just haven’t bought a tester yet. to give further context about its condition, in july 2023 it sat for a week or two, and an animal chewed the the fuel injector wiring on cyl 4. me being a naive teenager (still am, but have learned a lot of lessons), i drove that thing hard while it was misfiring terribly. ever since that has been fixed is when i’ve noticed the misfire at idle. ive wondered if that is still what’s causing the misfire, but it just seems unlikely that 2 separate, completely unaffiliated “mom and pop” type shops would both lie about diagnosing it with low compression

 

[Japanese]

Keep running the VRP oil, it can only help, not harm.
Can you find out if your intake or exhaust valves are leaking on those cylinders? Ask those two shops.

Can you pull out one of the valve covers, so we can see how dirty is the engine on the inside?

I'm not sure how the valves can be decarbonized without taking them out out, but some people on here may know.

 

[Faawrenchbndr]

i’m sorry if the way i wrote it wasn’t very clear, that’s my bad. i put restore and protect in this engine 600 miles ago, first time ever using this oil. the car has had the leaky valve issue for 25,000 miles/2years now, not related to the restore and protect at all. i’m just wondering if there are deposits that are somewhat keeping the valves sealed, and if the restore and protect will clean those off which will create an even bigger leak. spark plugs are fine, i replaced those recently too

So leaking valve SEALS?
Earlier you stated valve SEAT

 

[Kira]

A misfire at idle, which worsens with time, you say?
How does it run at highway speeds?

 

[RyanY]

Worst case scenario, you waste $30 on a jug of VRP. IMO it is worth trying for a few runs to see if anything improves.

Maybe also add a bottle of Techron as suggested above, followed by an Italian tune up. I doubt it will restore compression but if it is running okay just run it till it dies. At 257k it is on borrowed time anyway.

 

[nickaluch]

Just drive it use the cheapest 10/30 Dino oil you can get and drive it to the ground don't overthink it she's near the end