Hi so I’m new here and to cars but I have done a lot research and spent a lot of time trying to fix my current vehicle so here’s the story:

the first issue was code p0303 which was an engine misfire on cyl 3. I drove with that problem for 2 months becuase at the time my other vehicle was having issues. 

when I had a chance to work on the engine I first checked the spark plugs for cylinders 1 and 3 on the passenger side of the car. Each plug was soaked with oil so I replaced the valve cover gasket and seals. I also replaced the factory spark plugs with NGK Iridium spark plugs and NGK wires and coil pack. I also replaced the PCV valve becuase the car was burning oil at an alarming rate. I did an oil change as well and checked the fuel injectors to make sure they were functioning properly. After all of that work I tried to start the car and it cranks but would not start. It doesn’t make sense since it ran ok before I started this work. So I proceeded to replace parts. First a new battery, new starter( tested the old starter and it was bad so that was a good thing that needed replacing.

I also tested the crank and camshaft sensors for continuity which they both have and tested the sensors themselves for ohm resistance which they also have at the right spec. 
 

I checked the timing as well by positing the arrows on each gear at the 12 o clock position and they matched up perfectly. 
 

I also checked the ohms on the MAF and it also is good. 

I also performed a compression test on each cylinder and here are the results:

Cyl 3: 179 psi

Cyl 1: 156 psi

Cyl 4: 165 psi 

Cyl 2: 135 psi

i also tested each spark plug to test for spark and all 4 plugs get a consistent spark. 
 

I have no idea what is wrong with this car…any ideas or advice would be greatly appreciated.

I have not tested the fuel pressure but I did spray starter fluid into the intake and it did not start only crank. Fire did blow out of the intake though. 

 

Did you match the correct spark plug to the correct spark lead or coil pack?

That’s the first thing that comes to mind - something simple.

Those compression readings, did you only do them once or go around for a second shot? They seem to be quite wide spread for what’s considered anything healthy  

That’s all I’ve got. Hopefully someone can chime in and give some extra advice.

Cheers 

Bennie

Hi yes I matched the spark plugs and spark plug wires to the correct outlet on the coil pack as per the firing order of the car. On the passenger side there is 1 and 3 and on the driver side there 2 and 4. 
 

as for the compression I thought that as long as each cylinder reads above 100 psi then it would be considered healthy. Is that wrong?

Scan for engine codes or pending codes - post numbers here

Check vacuum hoses, PCV hoses for any leaks or disconnected or cracks - if the brake booster isn’t fully seated it won’t start - too big of a vacuum leak. 

Check for any disconnected wires from valve cover or other previous work. 

Check plugs and wires again. 

Compression should be within 20% of one another.  You’re over the compression difference threshold but 135 should start. But is it a legit 135?

To ensure good compression results the throttle should be open and use a power source besides the battery (jumper to a other car or power pack, etc).  Although a prime condition battery does work just fine. The last cylinder can test less than the 1st if the battery is getting drained from the first three cylinders tests. 

Was the throttle open and power source consistent?  Ideally each cylinder is tested 2-3 times to verify results.