code P0303 2004 v40
 

While speeding up at wot, car begin to shudder and surge. CEL blinked several times before it stay on. After this car would shudder under part throttle and while stopped at traffic lights.
I have done the following,
Changed plugs and gapped to .028.
Changed #3 coil.
Changed fuel filter.
Swapped #3 injector with #4 injector.
Test drove after each change. Only noticably improvement was a smother idle.
Car has 93500 miles and was last serviced at 90000 miles. Plugs. air filter, oil change and filter.
Plugs I took out looked good.
Did compression check and all cylinders were app. 170 on 4 revs.

Car still shudders, surges and bucks under wot.
Got the following codes after last drive:
P0303 (twice)
P0301
P0302
P0304

Any input greatly appreciated.

I have owned car since 51000 and these are the first proplems.

RE: code P0303 2004 v40
 

How about the other coil and the 2 wires?
The check engine light flashing means it is misfiring.

RE: code P0303 2004 v40
 

Will replace other coil tomorrow and order wires.
Thanks for reply.

RE: code P0303 2004 v40
 

Changed #4 coil. Went for test drive. No skip, no misfire, no bucking and surging. WOT from dead stop produces wheel spin and best of all NO CEL flashing or staying on. Hopefully problems solved with 2 new coils. Just dont understand why #4 coil would produce P0303 (which it did today after clearing last night) instead of P0304
Many thanks for input.

RE: code P0303 2004 v40
 

Glad all is good now. Not sure why it threw that code either but all that matters now is it is running good.

If you didn't replace the wires yet I would soon.

RE: code P0303 2004 v40
 

Am I missing something? On the '40's, how can you replace the coils without changing the wires. Its all one item.

RE: code P0303 2004 v40
 

No there is 2 coil packs and 2 ignition wires.

RE: code P0303 2004 v40
 

of course..... brainfart time!