SpiredFate
Junior Member
I should probably start this by providing a bit of background on my vehicle since I believe it may have ultimately resulted in my currently situation. I bought my Mustang at 32k Miles and have since put another 70k miles on it.
Early on in my owning the vehicle my radiator fan stopped working and caused me to run the car hot a few times until I got it fixed. I believe this may have resulted in warped heads and a slight valve tapping. I continued to run the vehicle with the slight valve tap for probably 2 years without any issues.
Then my belt gave out while on the interstate and again caused me to run the vehicle hot while I got to somewhere I could park and diagnose the issue (I did this by accelerating than putting the car in neutral and turning off the car and just coasting as far as I could before restarting and repeating.) After replacing the belt the car performed as it did before, with just a slight valve tap. Then about 2-3 months later this brings me to where I am now.
Initially I noticed the car stall when putting it in neutral coming up on a stop sign or turn from highway speeds. My CEL has always been on as a result of a Small EVAP Leak that I have not bothered with trying to fix, so I did not notice a change as far as my warnings go. However after the car stalled on me a second time as mentioned above I knew there had to be a problem and so I scanned the car and found P0300/P0308 codes (Random/Multiple Misfire & Misfire on Cylinder 8).
My first suspect was the spark plugs, as I had never replaced them and I doubt the previous owner had either since it was sold at only 32k miles. I replaced all 8 spark plugs as well as all 4 VCT Solenoids, yet the problem persisted though P0300 cleared. I then changed all 8 Coil packs and the problem continued to persist.
I decided it was time to perform a compression check. The values from my compression check are as follows; 1: 160, 2: 160, 3: 160, 4: 150, 5: 170, 6: 170, 7: 185, 8: 30. I also hooked up an air compressor to Cylinder 8 to try and identify where the leak was occurring to which the air was escaping through my vacuum line. I also noted when the compressor was hooked to Cylinder 7 a small amount of air escaping through Cylinder 6. I did not hook up the air compressor to any other cylinders. I should note that there is no coolant leak, though it does chew through some oil in it's current situation (without blowing smoke, none noticeable anyway).
As this is my daily driver I have disconnected the coil pack & fuel injector plugs for Cylinder 8 so that I may continue to drive the vehicle when necessary until I have a plan for repairing it. I am already planning to replace the cylinder heads on both sides as a result of the valve tapping, however I'm concerned that that may not be my only problem. I'm not sure if I should plan on a whole engine rebuild or what I should focus on doing here aside from replacing the heads. I'm also trying to find out what heads are suitable replacements, all the heads that I've managed to find on the internet are Gen 3 heads, so I'm not certain that they will work with my motor or not. I would also like to explore performance options, such as replacing them with BOSS or GT350/500 heads if possible.
Early on in my owning the vehicle my radiator fan stopped working and caused me to run the car hot a few times until I got it fixed. I believe this may have resulted in warped heads and a slight valve tapping. I continued to run the vehicle with the slight valve tap for probably 2 years without any issues.
Then my belt gave out while on the interstate and again caused me to run the vehicle hot while I got to somewhere I could park and diagnose the issue (I did this by accelerating than putting the car in neutral and turning off the car and just coasting as far as I could before restarting and repeating.) After replacing the belt the car performed as it did before, with just a slight valve tap. Then about 2-3 months later this brings me to where I am now.
Initially I noticed the car stall when putting it in neutral coming up on a stop sign or turn from highway speeds. My CEL has always been on as a result of a Small EVAP Leak that I have not bothered with trying to fix, so I did not notice a change as far as my warnings go. However after the car stalled on me a second time as mentioned above I knew there had to be a problem and so I scanned the car and found P0300/P0308 codes (Random/Multiple Misfire & Misfire on Cylinder 8).
My first suspect was the spark plugs, as I had never replaced them and I doubt the previous owner had either since it was sold at only 32k miles. I replaced all 8 spark plugs as well as all 4 VCT Solenoids, yet the problem persisted though P0300 cleared. I then changed all 8 Coil packs and the problem continued to persist.
I decided it was time to perform a compression check. The values from my compression check are as follows; 1: 160, 2: 160, 3: 160, 4: 150, 5: 170, 6: 170, 7: 185, 8: 30. I also hooked up an air compressor to Cylinder 8 to try and identify where the leak was occurring to which the air was escaping through my vacuum line. I also noted when the compressor was hooked to Cylinder 7 a small amount of air escaping through Cylinder 6. I did not hook up the air compressor to any other cylinders. I should note that there is no coolant leak, though it does chew through some oil in it's current situation (without blowing smoke, none noticeable anyway).
As this is my daily driver I have disconnected the coil pack & fuel injector plugs for Cylinder 8 so that I may continue to drive the vehicle when necessary until I have a plan for repairing it. I am already planning to replace the cylinder heads on both sides as a result of the valve tapping, however I'm concerned that that may not be my only problem. I'm not sure if I should plan on a whole engine rebuild or what I should focus on doing here aside from replacing the heads. I'm also trying to find out what heads are suitable replacements, all the heads that I've managed to find on the internet are Gen 3 heads, so I'm not certain that they will work with my motor or not. I would also like to explore performance options, such as replacing them with BOSS or GT350/500 heads if possible.
