1997 p38 4.0

Check engine light is on. Vehicle runs fine, starts fine, idles fine, speedo and tach are not doing anything strange.

Throwing code p1314 (misfire bank b damage cat) and p0306 (cyl 6 misfire detected).

Here is the freeze frame data for P1314:

rpm 1726
VEH speed mph 0
fuel sys 1 CL
fuel sys 2 OL
calc load% 53.33
ETC Fahrenheit 154
STPT B1% -2/34
LTFT B1% -7.81
STFT B2% 2.34
LTFT B2% -7.81

i reset the CEL twice and it reappeared both times in under 10 miles of stop and go driving.

Vehicle speed 0? Is that a VSS issue?

Thoughts on what i should check first?

 

From what you have posted......have you checked the fuse panel...under hood? I had this with my 95....burn and shorting relay. Sounds almost the same. Dam...can't remember which one....
I should be able to check tomorrow pm when I get home.

 

154 coolant temp when warmed up seems like a stuck open thermostat to me, or missing.

 

thanks to you both.

i will check underhood fuses, relays tomorrow.

interesting point about the coolant temp. i'm going to clear the codes, do another cycle, and pull the freeze frame data again tomorrow.

so far here is my plan:
check underhood fuses / relays
change all plugs (champion copper, right?)
bench test all 4 O2 sensors (flame and multimeter).
change fuel filter.

 

Could be - Crank sensor or bent tab on flywheel. any obvious missfire?

 

that's the strange thing chris. the car runs well. i've never detected any misfire or felt any stumbling. idle is smooth and it revs beautifully.

spark wires are about 3 years old. they were expensive but i forgot the brand. i'll test those when i change the plugs this weekend.

 

update:
new code P0306 (generic code) cylinder 6 misfire detected.
old code: P1314 (manufacturer specific code) misfire bank b damage catalyst.

 

a single cylinder misfire code sets at about a 2% misfire rate, the cat level damage on sets when misfire at 15% is detected. Here's pix of the tabs mentioned.