'97 Aurora - Cylinder 1 misfire (code P0131)

[mrbob]

I probably shouldn't be on this board because I am not a shadetree mechanic, but here is my problem.

'97 Autobahn, 108,000 miles, rebuilt transmission at 99,950.

Had plugs and wires replaced with A/C Delco parts 1.5 years ago at dealer.

Engine runs fine until 2 months ago. Hesitation and surging starts. No SES light. Thought I might have gotten some bad gas (had filled up at an old, never before visited station). After 2 weeks and new gas, things get worse (backfiring, more hesitiation). Took to dealer that did tune-up. Wires have lifetime warranty, so I was hoping that might be the problem.

They diagnose that Plug #1 is bad and replace it, for $178.00!!! (I know I got ripped - they claim labor, diagnosis time...) All is well, but I had been wanting to replace my FPR for other reasons (intermittant stalls), so about a week later a friend that is a "car guy" replaces the FPR for me.

Everything is great for about a month, then a week ago the hesitation starts again and 1 day later my SES light comes on steady. I get the codes pulled at Autozone and it's the P0301. They reset codes and after another day of hesitation, SES light shines again.

I have an appointment to see the dealer tomorrow for this, but my question is - What would be causing the same plug to go bad again? I have read about the backfire flap and how if there is a problem with it things could run hot and prematurely kill plugs. I should have asked for the old plug back from the dealer and this time, I will.

Any thoughts or suggestions? Thanks for reading.

-mrbob

[maxwedge]

P0131 is not a misfire code, related to o2 sensor bank 1 sensor 1?

[zimaad]

It could be a coil pack, plug wire, or plug. Maybe possibly the backfire flap too. I Woulnd't expect a bad FPR to trip a code for one cylinder. It's not too too high for $178 for a plug wire. Reason I say that is that a set of OEM plug wires is $100-150 to begin with. Cylinder one is in the rear passenger side of the engine and isn't the easiest to get to. Not the hardest, but you definately have to remove some stuff to get at it. Still a little high. It probably takes me a good hour and a half to two hours to change out all my plugs/wires...then again, I'm not a pro. Also, coil packs are cheap(around $30 probably at advanced/autozone) and are easy to do. You could possibly do it yourself or get your car buddy to help out. The coil packs have the number of the cylinder they go to on them. There is one hard bolt to get to behind the coil packs, but doable. The intake flap is a little more work. Cheap part and a little time to fix. Anyways..goodluck. If you have any question, don't hesitate.

[mrbob]

Originally Posted by maxwedge

P0131 is not a misfire code, related to o2 sensor bank 1 sensor 1?

My big mistake/typo - it was P0301 Cylinder 1 Misfire Detected

[mrbob]

Originally Posted by zimaad

...It's not too too high for $178 for a plug wire. Reason I say that is that a set of OEM plug wires is $100-150 to begin with...

I should have specified, all they replaced was the #1 plug, not the wire. And I confirmed that they used an A/C Delco plug (but what else would you expect from a Chevrolet dealer?)