My Xj has been hard to start and when trying to get up to highway speeds or when you bring up the RPMs the CEL starts flashing then it will start to misfire bad, run very poorly and very hard to accelerate, I ran my code reader and got 5 codes

PO353- IGNITION COIL C Primary/ Secondary circuit malfunction

PO300- multiple misfire detected

PO303- cylinder 3 misfire

PO304- cylinder 4 misfire

PO455- Evaporative emission system leak detected (gross leak / no flow)

any help is greatly appreciated as the car is my daily driver

I was thinking it could possibly be a clogged cat

 

You likely have (at least) 2 problems. The main one is causing the misfires/driveability issues and the P0455 is a leak in the evap system. They are most likely not related.

So you know, a "flashing check engine light" indicates a serious misfire, which if not resolved quickly, will destroy the catalytic converter and then you'll have bigger fish to fry. I'd park this vehicle until you get this figured out.

There are a few possibilities, but I'd start by performing a very close inspection of the connectors and wiring leading TO the coil rail. I've seen coil rail connector issues on the 2000-2001 cause the P0353 code.

Also, have to ask. Have you been needing to add coolant to the coolant reservoir? The 0331 cylinder head issue with the 00-01 XJ can create misfires on cylinders 3-4 and the symptom that you usually see first is unexplained (not a leak) loss of coolant.

The P0455 could be something as simple as a gas cap not sealing properly or it could be any one of a number of evaporative system components failing including a rotted hose, faulty charcoal canister and a few other evap system components. If you get stuck diagnosing the P0455, a shop can perform what is called a "smoke test" which makes pinpointing the root cause of the leak easier. I'd consider putting the P0455 on the back burner for now though and spend your time and effort concentrating on the other more important codes first, especially as this is a daily driver.

Good luck and keep us posted!

 

X2 on checking the wiring, and check through the oil cap to see if you have the common crack. I think 3 and 4 are on the same coil. Could swap coils and see if the problem moves.

 

Ok Swapped out my ignition coil and plugs with NTK parts and she’s been purring like a kitten since thanks for the help!