random knock then randomly dies?

[sacline]

Hello. I am having this weird issue. I can start my car just fine and drive it for a while with no problems. After i shut it off and lets say run into a store and come back out and start it, its starts but then a knock noise happens and dies. I then restart it and give it gas to not die and drive away...after a minute the knock goes away and runs just fine. This is random and its pissing me off. New plugs, wires, coil, slave cyl, no boost leaks.. what's going on? Thanks for any help.
Also it sounds like its the first cylinder that knocking. Compression tested it and it read 90psi. Thing is the car pulls hard and runs great. Besides that i want to know why the random knock and random dieing....

 

[Joshky9]

90 psi is below service limit. Is that in one cylinder or all 4?

 

[sacline]

Just on cyl 1. Others were 140. Drives just fine otherwise. Still has power. I know i have a bent valve or something but i dont get why im having this random knock and dieing bs. This car is frustrating....specially wen its my dd and im broke...

 

[undefined0000]

Don't think any car would run correctly with a bent valve . Knock could be the piston kissing the valve.

 

[sacline]

Right but it only does it randomly. And only at idle. When the noise happens it goes away after i drive. If the piston was slapping valves wouldnt it do it all the time....? Any reasons on why the random dieing?