3800 Could this be related to bad fuel?

[Bru]

Under any type of load the engine will buck and shake. It feels like a misfire but I didn't have my scanner on me when I came into the office this morning so I couldn't check which cylinder(s). There's no check engine light flashing.

When my plug wires were bad it would misfire only when I hit boost. This time it does it under any load at all. Even when the TCC kicks in at 45 mph it stumbles.

I put in a full tank of premium last night, and yesterday before filling up the car was running normally. All plug wires are tight and nothing has burnt through on the headers. That's the only check I gave it this morning when I got downtown.

Click to read more...

 

[Bru]

Also, plugs and plug wires are a few months old and haven't been touched. I know the plug wires are finicky when they're on and off a bunch, and I haven't touched them since they went on.

 

[UWISHU1]

you didn't fill up at Speedway did you?

 

[Bru]

Nope, filled up at BP.

 

[bikrboy128]

clean the MAF off? or you could unplug it and drive the car to see if it runs better.

 

[PANDA]

I had a issue like that a few months ago. I could really feel it during light acceleration in 4th gear. Like merging onto the highway or accelerating up a hill. The torque converter was locked and I was almost in boost I guess. Changing plugs didn't do anything, and resetting the tune to as stock as I can make with my setup didn't change a thing either, if anything that made it worse. Not sure if it was the winter gas, or a problem with my trans, but I haven't experienced this before. I ended up changing some 4th gear TCC settings with the tuner to fix/coverup the issue.

I will move this to 3800 section...

 

[Bru]

I'd rather keep it in repair. Please ask before you move it.

 

[Turbocharged400sbc]

it very well could be caused by small amounts of water in the fuel...also just as likely that saltwater spray got on yer coilpacks and you may have a weak dielectric somewhere... did it happen with wet/salty roads/particularly large puddles?
when its dark out look for any lightning

certainly sounds like a misfire....

 

[Bru]

I had to reverse pretty hard in snow this morning to get out off the driveway and spun the tires. Maybe it threw some snow into the engine compartment.

It definitely feels like an ignition misfire.

 

[Turbocharged400sbc]

cold motor? aka KR not enabled?

 

[Bru]

Coolant temp was 160-plus degrees. The engine was warmed up for 15 minutes.

 

[Turbocharged400sbc]

good its also possible thatwhile warming up water from the cowl area dripped onto the rear wires etc.

it may shock ya but ground yerself take and run yer hands along each ign calble in turn and see if you find any voltage leakage you can do the same thing with a grounded wire/etc but by hand you can feel the tingle of small voltage leaks easier (aka an arc point not arving unless under load/high kv

 

[Bru]

Excellent. Thanks for the info, James.

It's been sitting in a parking garage since 9am, so maybe some of that moisture has evaporated.

 

[Turbocharged400sbc]

dry salt is alot less conductive than wet lol

pull yer wires from the coils and look for moisture...if the connections are at operating temp (ambient eng compartment temp) and saltwater splashed on em the cooling can wick the shit up into the boots/connections (this is true even with weatherpack connectors)

 

[Bru]

Gotcha. Will do.

 

[blakbearddelite]

Did you have time to scan it yet?

 

[Bru]

Naw, not yet. I got home last night and crashed. I looked at the coils and plug boots this morning and didn't see anything out of the ordinary, but they did come off easier than I remember.