Hi I’m new to the group, I own a 2005 4th gen 4runner limited with the 2uzfe. I’ve owned the car going in 6 years with no issues other than an intermittent P0430 which usually went away so I ignored it. 5 months ago I replaced all the spark plugs with oem from the dealer in an attempt to improve my mpg etc. since then i noticed a slight change in performance, rougher idle, intermittent stutter on cold starts, lower mpg’s. However for the first 4 months it wasn’t showing any codes, I also replaced the pcv valve in that time. A week ago I decided to get it scanned and it showed misfire on cylinder 4 so I swapped around the coils, that didn’t resolve it, then I replaced the spark plug thinking it may have been faulty. That didn’t fix it.
I just did a compression test with the engine hot on all cylinders, cylinder 4 is only showing around 100psi, all other cylinders are showing around 170-180psi.
After the engine cooled down I did a wet compression test on cylinder #4 I’m still seeing the same compression (around 100psi).
I’ve also tried a cylinder leak down test on #4 at TDC which hasn’t given any conclusive results, aside from hearing/feeling air escaping into the neighboring cylinder #6. No bubbles in cooling system, no air escaping from oil fill spout, throttle body, or exhaust as far as I can tell.
Seeing that the compression on cylinder #6 showed normal pressure (around 170-180PSI) I’m confused as to why I’m feeling air passing into it from cylinder #4 durning the leak down test.
Thank you!
I just did a compression test with the engine hot on all cylinders, cylinder 4 is only showing around 100psi, all other cylinders are showing around 170-180psi.
After the engine cooled down I did a wet compression test on cylinder #4 I’m still seeing the same compression (around 100psi).
I’ve also tried a cylinder leak down test on #4 at TDC which hasn’t given any conclusive results, aside from hearing/feeling air escaping into the neighboring cylinder #6. No bubbles in cooling system, no air escaping from oil fill spout, throttle body, or exhaust as far as I can tell.
Seeing that the compression on cylinder #6 showed normal pressure (around 170-180PSI) I’m confused as to why I’m feeling air passing into it from cylinder #4 durning the leak down test.
Thank you!
