[Cabover1000]

Unplug your maf and see if it runs good without it.

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[be39rad]

What does the MAF do?


"That almost looks right"

 

[bobdmac]

I may have missed this, but it's still not clear to me what codes have re-appeared. Are they the same original four?

 

[be39rad]

No, different codes keep coming up. Except P0300, and P01250 or whatever it is. Besides those, different codes for different individual cylinders will keep popping up.


"That almost looks right"

 

[Cabover1000]

What does the MAF do?

"That almost looks right"

It tells how much air is being pulled into the engine.

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[bobdmac]

My knowledge in this department is only superficial, but here's what I think, and maybe others with more experience can chime in. Misfires spread over several cylinders are, by definition, caused by something that affects all the cylinders, which typically means an intake manifold vacuum leak or a fuel pressure problem. Simultaneous coil failures in three cylinders is pretty unlikely.

In this situation, with the codes changing specific cylinders, rather than the OBD reporting "multiple misfires," (more typical of a vacuum leak) it sounds like individual injectors are shutting down. The deterioration in drivability under increased fuel demand (depressing the gas pedal) makes it sound like a fuel pressure problem, and I agree with Poolman that you need to test the fuel pressure, but not just at idle, since it seems to idle okay, but stepping on the gas seems to provoke the problem. If the fuel pump isn't creating enough pressure, or the fuel filter is clogged, it may run okay at idle but be unable to keep up with the fuel demand under heavier load.

In most states, you can go to an auto parts store like Autozone or O'Reilly's and borrow a pressure gauge to hook onto the Schrader Valve on the fuel line. You could have someone read the pressures while you have your foot on the brakes and give it gas. I don't know the specs for normal pressures, but Poolman probably does.

As for the MAF, I suppose it's possible but this sounds different. Supposedly, if you unplug it and the drivability improves, that implicates the MAF, but I don't know how reliable this test is.

At any rate, if some of the more experienced forum members disagree with this, I hope they'll correct me.

 

[bobdmac]

Also, I don't know whether this is consistent with the OBD codes you're getting or not, but at 196,000 miles, given the way performance deteriorated gradually, it may be the catalytic converters. Just something to consider.

 

[be39rad]

Poolman

So i tried the fuel pressure tester at the valve at the top of the rail, and the tester i got from autozone wouldnt fit. I had the bit, tightened it on there and it wouldnt stop leaking. All was tight as possible. Due to leak, did not get any readings.


"That almost looks right"

 

[be39rad]

Well guys, i think i might have this solved for now. Every time i read the codes, EVERY TIME, coil pack number 4 came up as a misfire. I just replaced that with a brand new one rather than used, and car runs like a race car again ha. Crossing my fingers, hope that is the fix for a while....or at least till the nect coil pack died. This is why i asked the Q in the begining if a misfire in one cylinder could cause one in other cylinders.

Thanks to all of you for helping me !!!!


"That almost looks right"

 

[Cabover1000]

Well guys, i think i might have this solved for now. Every time i read the codes, EVERY TIME, coil pack number 4 came up as a misfire. I just replaced that with a brand new one rather than used, and car runs like a race car again ha. Crossing my fingers, hope that is the fix for a while....or at least till the nect coil pack died. This is why i asked the Q in the begining if a misfire in one cylinder could cause one in other cylinders.

Thanks to all of you for helping me !!!!

"That almost looks right"

Thats good. I hope it works good for a while

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[poolman]

Stumped me when you stated you where getting misfires from about every cylinder--Glad your problem is solved,,along with ,it being a very easy fix for you.