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Weird Misfire


W-Body Andy
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My 1994 regal with 85,000 miles has developed a very odd misfire. I bought the car and it had sat for a few months before I got it. I replaced the icm with a junkyard one (tach signal to computer was reading wayyyy to high), spark plugs and wires with AC delco stuff, and an egr valve because it was causing a super terrible misfire. I had dropped the transmission pan and changed the fluid and filter. Anyway, I’ve been driving the car for around 700km now, and decided since I am no longer having any issues, I should go wide open. So I floored it getting onto a highway from around 10-60mph. No issues. Made it home, shut it off, and then went back out 10 min later to go to the store and when I started it it was running on maybe 5 cylinders? But started running fine after 15-20 seconds. This only happens when it’s hot. If you are out just cruising and shut it off it doesn’t do it. Only if you either let it sit and idle and get hot or drive it hard and it gets hot. (Note that the gauge isn’t even making it to the middle (100° C mark). I figured a coil was shitting itself, but after swapping them around with a junkyard coil, it was the same. 
 

I have no idea what it is. It’s odd to me that it happens only when warm, and only for like 10-15seconds 

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Connect a scan tool.  Look at the data stream.

Verify fuel pressure.

Would be worth inspecting plugs, wires, injector harness, etc.

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7 hours ago, Schurkey said:

Connect a scan tool.  Look at the data stream.

Verify fuel pressure.

Would be worth inspecting plugs, wires, injector harness, etc.

Alright, will do. Also picking up a scan tool soon

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So misfire only on hot soak restart for a short time. Coil would be my thought too. Possibly a leaky injector flooding a cylinder and once the fuel clears up, no more problems. Hot and throttle snap fuel pressure is also suspect, as @Schurkey mentioned.
Do scan tools offer mis counters on obd1? I mean it’ll be helpful regardless to monitor mixtures and inputs, maybe WOT O2, and coolant temp during hot restart but you have some other diag avenues still.

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