Saleen304
forum member
- Joined
- Aug 11, 2011
- Posts
- 451
- Reaction score
- 2
I am getting random and specific misfire codes on my 2005. Codes are either P0300 (random) or specific to a cylinder (P0305, P0303, P0306, P0304). Seems like cylinder 5 gets the code most often. I have tried the following:
1. Replaced all coils with new motorcraft coils
2. Replaced new brisk plugs with new Ht0s gapped at 0.030"
3. Checked tune (Lito)
4. Replaced EVAP purge valve
5. Checked for vacuum leaks (16.4 Hg at idle)
6. Replaced cam position sensors
7. Replaced crank position sensor
8. Checked grounds for PCM and crank position sensor ground shield
9. Had MAF checked (PMAS HPx)
10. Checked injectors (Bosch 1000cc injectors were installed Aug 2015). I replaced them with 60lb/hr injectors I had available. Adjusted tune, issue did not go away.
11. Disconnected vct solenoids. Problem did not go away.
12. Compression check. Ave 199. 1- 200, 2- 208, 3- 199, 4- 196, 5- 199, 6- 192, 7- 200, 8- 207
Problem showed up this year at a HPDE event in May and have been fighting it all year. I could replicate it on the street by holding 4000 rpm in 3rd gear for 4-5 seconds and the check engine light would start flashing and I could feel the misfire. Would take 10 sec or so to go away. Lately it comes up more often even if I just drive normally. Datalog shows it holding steady at 14.7 A/F and then go lean when the misfire happens. This does not occur at wot. Has anyone had an issue similar? What are my next steps?
1. Replaced all coils with new motorcraft coils
2. Replaced new brisk plugs with new Ht0s gapped at 0.030"
3. Checked tune (Lito)
4. Replaced EVAP purge valve
5. Checked for vacuum leaks (16.4 Hg at idle)
6. Replaced cam position sensors
7. Replaced crank position sensor
8. Checked grounds for PCM and crank position sensor ground shield
9. Had MAF checked (PMAS HPx)
10. Checked injectors (Bosch 1000cc injectors were installed Aug 2015). I replaced them with 60lb/hr injectors I had available. Adjusted tune, issue did not go away.
11. Disconnected vct solenoids. Problem did not go away.
12. Compression check. Ave 199. 1- 200, 2- 208, 3- 199, 4- 196, 5- 199, 6- 192, 7- 200, 8- 207
Problem showed up this year at a HPDE event in May and have been fighting it all year. I could replicate it on the street by holding 4000 rpm in 3rd gear for 4-5 seconds and the check engine light would start flashing and I could feel the misfire. Would take 10 sec or so to go away. Lately it comes up more often even if I just drive normally. Datalog shows it holding steady at 14.7 A/F and then go lean when the misfire happens. This does not occur at wot. Has anyone had an issue similar? What are my next steps?
Last edited: