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biocomet127
11-06-2017, 10:51 PM
So I’ve been haveing this problem with my 1999 legacy gt for a few days now. I was driving my car around with some aggressive drive and as I’m climbing a small hill at 55 the car misfires. And then it starts misfireing left and right so bad to the point I had to pull over because I thought I was going to break an axel. After pulling over the engine sputtered for a few minutes and died and would not start and stay running. I was able to limp the car home but the engine still misfire every now and again. This it where it gets weird. When the engine wasn’t running like crap you could take it all the way to redline without a problem and then for no ruyme or reason it would misfire. I check fuel pressure before and after the filter and both where good. After some research I replaced the crank position sensor and the car ran right as rain. I put 60 ish miles on the car and the problem returned and I can not for the life of me figure this problem out. Some help would be greatly appreciated

Sub-Goon
11-07-2017, 03:04 AM
Could be your coil going out? I'd meter the resistance in your coil wires too.

Huffer
11-07-2017, 02:29 PM
Summary of the issue:
1. Car running fine, then major misfire.
2. Replaced crank position sensor.
3. 60miles later, misfiring again
Sound about right?

Have you checked:
spark plugs
coilpack
oil condition - check for metal/filings, internal engine damage?
cylinder compression
knock sensor

biocomet127
11-07-2017, 07:08 PM
Thank you for the reply’s. So I was thinking that the coil was the problem but the car isn’t throwing a code for that. The only codes are for the secondary o2 sensor ( which I broke and a generic Evap code. I pulled out one spark plug and it didn’t seem bad. Defiantly not new but it should work fine. I’m replacing them any ways. If the coil was bad I’m not sure why replacing the crank sensor would fix the problem for 60 miles. That’s what’s really throwing me off. Last night I took a big jug of water and put it on ever wire on the engine that I could find and there was no change to the condition. Could it still be a bad coil?

Huffer
11-08-2017, 09:25 PM
The misfire could be that the timing belt has jumped teeth too. Don't just consider it an electrical issue. You really need to examine everything that contributes to ignition, and continues the ignition of each cylinder during the rotation. Check every sparkplug, not just one. Check the oil...

biocomet127
11-12-2017, 11:46 PM
It can’t be a skipped timing belt because it would consistently run like crap. (And I just redid it) It’s not a constant misfire. Out of 10000 cycles maybe 1500 of them are misfires and it’s generaly only after being driven hard. I put 93 octane in the tank the other day and that seems to help it a lot but still didn’t fix the problem. Now instead over the problem starting and staying it happens every now and again. The other day I replaced the spark plugs and I haven’t been able to recreate the problem since so I guess it’s fixed but something makes me feel like it’s still not 100% it still feels like it’s a little down on power. You wouldn’t notice it unless you drive the car every days and it also feels like it doesn’t run as smooth.