BIke, if you have cleared the issue, it will take 5 complete drive cycles (around 10 minutes of driving each time) and then on the 6th start, as long as the fault has not returned, the light will clear on its own. Granted, the codes are going to be stored in the computer still. So, you can either get a code reader and clear them manually or you can momentarily disconnect the battery from the car and reset them that way. Granted, if you disconnect the battery, you will need to reset your auto up/down on your windows (easy to do, if in doubt, ask here).

 

Thermo,

Thanks for the reply sir. I just took a 10 hour trip. Atlanta to Starkville Mississippi and back. Had to pick up my daughter for spring break. I'm taking it that the trip only counted for two of the 6 drive trips no matter how long they were?

 

Hi There,

I'm having same issue with my S-Type 04 94K miles. The only difference is the Misfire is on one side 1, 3, and 5. + Bank 1 and Bank 2 Lean.

Little Background, I used Gumout Fuel System Cleaner in my car and filled up the tank, drove about 2-3 miles and car lost power, idles very rough, restricted performance, flashing check engine light.

Could a clogged fuel filter cause misfire only on one side or it more sounds like a vacuum leak?

Thanks!

 

Rizwan, before we start jumping to potential problems, what are the codes? This may provide a little bit of insight.

As for a clogged fuel filter causing issues, that is a potential. This is where connecting up a fuel pressure gauge would be advisable. You should see around 40 psig with the engine running. If it is less than that, then you probably have a clogged fuel filter. Granted, for the cost of a fuel filter, it would be a quick thing to replace and would remove any question as to that being the issue, especially if you haven't replaced it in the last 15K miles.

The misfire could potentially be a vacuum leak, but you normally get a P0171/P0174 error code too if it is bad enough to cause a misfire. You don't mention that.

 

Check all wires on the THrottle Body Sensor (pay extra attension to the yellow one) It breaks but stays in the plug, held only by the rubber gromit...common issue and gives fales codes thus making you chase your tail!

 

You didn't have P0171 and P0174 earlier because oxygen sensors were not working.
Before you spend another $$$$ on parts you have to be absolutely sure that you don't have vacuum leak, because it is primary cause of there errors.

So, you did change IMT valves seals and PVC hose, but did you check PCV valve and valve that goes to brake booster? Brake booster vavle is brittle and tends to break, at least you should seal it if you find it leaks.

But before you buy anything listen to hissing noise or do a smoke test.

When do you get misfire codes? On idle or acceleration? What are your fuel trims (you can read them with OBD scanner).They are surely more than 20% but how much? Misfire can be due to running too lean. Maybe leak is so severe that ECU can't correct it.

edit: I see that somebody has already written about brake booster hose, anyway everybody with these errors should check it.

 

And the big thing about an air leak is that fuel trims will be high at idle but drop as you rev.