I still am having an intermittent issue with RMP dropping at red lights, and if I try to accelerate the car continues to pop, pop, pop while raising RPMs.
Yet when it idles right its a dream. I just don't know what causes this and I've tried various things to chase the issue. I first thought I was losing fuel pressure since I was hearing and feeling a bam, bam, bam from the rear when ever this happens and I'm in motion. I upgraded to a Walbro 190 LPH and it didn't change anything.
I swapped out the stock Motorcraft ignition coil with a Accel. I swapped 8.5 mm MSD wires for 9 mm Ford racing wires. I swapped the cap and rotor which had white crust inside with new Motorcraft cap and rotor. A few days ago I had a local muffler shop swap out my X pipe with a stock Mustang H pipe and connect the air system to the rear cats with a brand new stock steel pipe.
Today for the first time in a week, I was at a red light and the RPMs dropped again to an almost stall. I was right at the entrance to the parkway so I got on and brought the car up to 55 mph and there was a definite pop, pop, pop and bucking as I tried to cruise. I could feel like it might stall so I pushed the gas and accelerated for about 10 seconds. I felt pop, pop, pop then it smoothed out and I felt clean acceleration. The care drove great the whole way home. As soon as I got home I immediately threw the code scanner on and took readings. KOEO 11, CM 11, KOER 41.
I expected there to be something in CM since the car had definite problems while running. But the only code coming up is 41 which I know from past experience is a lean condition and a PITA to fix. I don't get it. I dropped a crate motor in last summer, checked and verified TAB TAD setup is working 100% correctly, was getting all 11's on every code scan from last summer till today. Its possible the muffler shop could have left the O2 wire too close to the H pipe and melted the wire. other than that I have no idea what this is or why its happening.
the air tubing that goes to the back of the heads was clogged solid when I pulled it last summer, I cleaned it out before putting it back on the new crate motor. The O2 is grounded to the back of the heads exactly as its supposed to be. I cleaned the paint from that spot and put a thin film of grease to keep it from rusting too fast. And it was a brand new Denso O2 with stock connector, not a universal with a butt connector.
What am I missing or not checking in this situation? I love how the new motor runs when its running right, which is about 98% of the time. But these intermittent fits are ruining the driving enjoyment for me.
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