aaronth777
Proven Member
- 92
- 27
- Apr 12, 2015
-
Dayton,
Ohio
Hello all. I've been trying to diagnose my car for 2 days now and reading through all the forums I can find, but I'm running out of ideas. I apologize in advance for the long post, but here's what happened:
I'm driving my 98 GSX like any other day, then one day at a stop light I noticed the idle felt slightly off. Nobody else would notice it, but I know this car very well. Then pulling off from the light about 200ft and I lose almost all power. It stalls a few times but I manage to get it home since I just pulled in my neighborhood. I try to run it a few times but it hasn't ran properly since that happened. It threw a cylinder 3 misfire code p0303 when it first happened, but no codes since then.
My first thought is to pull up ecmlink and see what's going on. I noticed that if I use link to turn off injectors 2 and 3, it barely changes if at all, but if I turn off 1 or 4 then the car dies. Sounds like a coil pack so I pull them out and test them. They test fine, but I swap them with each other to see if anything changes. Start the car back up and nothing changed (2 and 3 still not doing anything). I swapped around plugs, wires, ecu, and ptu but nothing changed. I tested spark on all 4 cylinders and they all have spark, so I don't think that's the issue.
I pulled out the fuel rail but kept the injectors in the rail. I unplugged the coil pack and turned the car over a few times. All the injectors seemed to put out the same amount of fuel on the rags, so each cylinder is getting fuel.
So it has fuel and spark, my next thought is timing. I change the CAS for a new one but it didn't solve it. I did notice that if I unplug the CAS while it's running, nothing seems to change which seems strange to me, but would that cause only cylinders 2 and 3 to misfire? The timing belt is tight so I don't see how it could have skipped teeth, or why it would only cause 2 and 3 to misfire. I tried locking the car in open loop mode as well but didn't change anything.
I haven't checked compression yet, that'll be my first test tomorrow. Is it possible the headgasket could have blown between the two cylinders? The coolant level hasn't dropped, and I haven't seen any noticeable smoke from the exhaust. Last thing I can think of is a vacuum leak, but again why would that only affect cylinders 2 and 3?
I've already spent 2 days and $200+ trying to fix this. I can't afford to keep throwing money at it so I'm looking for advice to see if there's anything I may have missed. I do have data logs before and after this happened, in case anyone wants to see them. Thank you!
I'm driving my 98 GSX like any other day, then one day at a stop light I noticed the idle felt slightly off. Nobody else would notice it, but I know this car very well. Then pulling off from the light about 200ft and I lose almost all power. It stalls a few times but I manage to get it home since I just pulled in my neighborhood. I try to run it a few times but it hasn't ran properly since that happened. It threw a cylinder 3 misfire code p0303 when it first happened, but no codes since then.
My first thought is to pull up ecmlink and see what's going on. I noticed that if I use link to turn off injectors 2 and 3, it barely changes if at all, but if I turn off 1 or 4 then the car dies. Sounds like a coil pack so I pull them out and test them. They test fine, but I swap them with each other to see if anything changes. Start the car back up and nothing changed (2 and 3 still not doing anything). I swapped around plugs, wires, ecu, and ptu but nothing changed. I tested spark on all 4 cylinders and they all have spark, so I don't think that's the issue.
I pulled out the fuel rail but kept the injectors in the rail. I unplugged the coil pack and turned the car over a few times. All the injectors seemed to put out the same amount of fuel on the rags, so each cylinder is getting fuel.
So it has fuel and spark, my next thought is timing. I change the CAS for a new one but it didn't solve it. I did notice that if I unplug the CAS while it's running, nothing seems to change which seems strange to me, but would that cause only cylinders 2 and 3 to misfire? The timing belt is tight so I don't see how it could have skipped teeth, or why it would only cause 2 and 3 to misfire. I tried locking the car in open loop mode as well but didn't change anything.
I haven't checked compression yet, that'll be my first test tomorrow. Is it possible the headgasket could have blown between the two cylinders? The coolant level hasn't dropped, and I haven't seen any noticeable smoke from the exhaust. Last thing I can think of is a vacuum leak, but again why would that only affect cylinders 2 and 3?
I've already spent 2 days and $200+ trying to fix this. I can't afford to keep throwing money at it so I'm looking for advice to see if there's anything I may have missed. I do have data logs before and after this happened, in case anyone wants to see them. Thank you!
but since it was cylinders 2 and 3, the obvious first thought is a bad coil, but just a possibility it could be a headgasket blown between the cylinders.
