Picked up a 03’ with 59k miles. The car ran fine for the first day. Previous owner said it had say for a quite some time. So I added some fuel system cleaner and topped off the tank with fresh premium. That’s when my problems started.

car is throwing codes:
p0505 - idle control system malfunction

p0301 - cylinder 1 misfire detected

p0304 - cylinder 4 misfire detected


Driving, the car is very hesitant, severe lack of power, very sputtery.

So far I’ve done:
New Plugs
New Coils
Adjusted Valves
Checked TPS Voltage.

Cyl 1 and 4 seem to be running lean, and much hotter. it’s damn near smoking my plugs.

Any ideas what I should do?

 

Also, compression test was 242 across all cyl.

 

Move the coil packs around and see if the mis fire follows. If the same cylinders show mis fire again I’m betting it’s the fuel injectors especially if the car has sat for a while. Change spark plugs too.

 

Ive already swapped packs and plugs. I’m thinking you’re right about the injectors

 

Sat for a long time means injectors are gunked up. Fuel turns to varnish if it sits. Very difficult to remove.

Easy to test by removing injector, plug back in and place into cut open water bottle. Watch spray pattern when turn on key.