The Mistress has been driving code free for the past year since going back into the office full time. But over the past few weeks, she began acting up. Started with P0304, 305, 307, 1316, 1647 but no issues with acceleration, engine knock, etc - just the CEL, restricted performance and those codes when checked. After about 5 minutes, the Restricted performance and amber warning light would clear. Have the O2 sensor on hand to replace when it warms up so decided to start with new plugs since these had been in there for about 18months (car was only driven once a week for about 10-15 miles round trip while I was teleworking). Old plugs weren't bad but replaced anyway. cleared codes and drove fine for about 8 days. Last week, during some crazy cold weather here, noticed transmission slipping when accelerating from a stop, but once car warmed up. Figured transmission might be due to cold so scheduled in for service later this week.

Today on the way home from work, she started fine but at first red light engine sounded terrible, vibrating and like it wanted to stall but never did. Got the Restricted Performance and checked codes, this time add in a P0354, 356, 357 (Coils D, F G primary/secondary circuit). Also when the RP came on, the CEL began to flash for about 20 seconds and then cleared along with the RP. Continued the drive home via slower back roads and this happened 2 more times. Transmission slipped a couple of times as well. Will drive son's car for the next few days, then spend some time this weekend trying to assess the situation. Will start with swapping coils around, but also considering options, love the car, been 9 years since transmission was rebuilt,

I've had her 14 years, put over 100000 miles on her myself (bought with 91500 and currently at 197854) - may be time to move on (another of course)

 

It could be a wiring problem.. Check the cable harnesses, especially the one that goes to the coils on the passenger side (for LHD cars). Sometimes it wears against the cylinder head and causes a short circuit to ground.

 

true and have had to wrap some of the wiring on the drivers side harness due to insulation becoming brittle and flaking off. always good to double check.

 

Flashing MIL typically means severe misfire doing cat damage.

Misfires can cause bad gear changes as the PCM & TCM need to cooperate for smooth ones and misfires wreck that.

So... fix the coil/etc faults.

 

and so the saga continues. Have been driving my son's tank since this occurred and took today off to try and investigate the issues. With the misfires - no dang wonder looking at the harness. Taped up harness as best I could and started her up, checked codes and only showing 1647 for the upstream O2 sensor.



Took it around the block just to see if any misfires occur and just as I'm turning into the drive, transmission slipped and refreshed codes with a new one - which already had an appointment to get checked out.


not sure if I will rebuild again or throw in the towel. Have seen a few nice ones for sale.

 

does anyone have the coil harness part number? I did find a set 8 of pigtails for $40 or a complete harness for coils and injectors for $200. Thinking complete harness would be the way to go but can you just replace the harness to the coils or is it easier to replace with the injector connections?

My concern with the pigtails is that how much of the harness that isn't visible is already degraded, so cutting/splicing a pigtail in will only fix what is visible

for the transmission may just say the hell with shop and DIY. Found a couple of transmissions - 1 for $2100 includes shipping with 1yr/12000mile warranty; one on eBay for 850+ 300 shipping, no warranty and 80K+ miles. Will call Erikkson's Monday or Tuesday to see if they have any and get pricing. Shop will probably put me out 5K or more

 

Misfires can upset the trans (because it & PCM need to co-operate but PCM needs no misfires), so fix the O2 sensor etc and trans may be fine after a few drives.

 

that's the plan, just prepping for the worst case

 

thanks, will do and will reschedule shop visit for transmission, just pricing out transmissions prepping for the worst case scenario.