On a scale of meh and Full panic over DTC's....

[RustyNutz]

How worried should I be? Ran to get lunch today. Pulled out from side road, 3/4 acceleration to 65, leveled off and slowed to a stop at a redlight 1 mile up. Stopped at the redlight, suddenly engine idle drops to 400ish and shakes badly. I put it in neutral, it idles slightly better but is def rough and not right, rev it up to 1k and it feels smooth but not right.

Baby it on the drive home, it feels as if it is in limp mode. No check-engine light. I stop halfway home, turn the truck off, then back on, and it idles and drives like normal.

Scanned DTC's once I got home, and found P0018 and P0021 as history codes. Cleared them, test drive - everything seems fine.


So....whats the chances of just an intergalactic glitch, vs something more major about to rear its ugly head?

 

[RustyNutz]

2018, 17k miles. MPT 93 tune with about 1k miles used, and M-12405-35T plugs installed about 700 miles ago. TBH, i swear the idle suffered a bit when I changed the spark plugs: I checked all gaps but have always been a bit suspicious that one may be not quite right. I noticed the spark advanced shown in the Nguage will bounce at idle, since the plugs

 

[Tr4ckD4ys]

subscribed. Looking to order those sparks from offroad alliance and swap them in soon. Also concerned about gaps...

 

[Bozz]

My first guess would be gas. I've had my little convertible roadster for almost 14 years, still mint condition. Special ordered it. In that 14 years, 2 different times I put mid-grade gas in it. BOTH times.......backfiring, chugging, limp mode, etc. I will NEVER put mid-grade gas in another vehicle EVER! I think it is the least favored gas and sits in underground tanks the longest and gets contaminated. That's my theory.

 

[isis]

Mid grade gas just mixes premium and low grade. It doesn’t have its own tank.

 

[xrocket21]

limp mode. no big deal. reset the ecu by disconnecting the battery.

 

[Bozz]

Mid grade gas just mixes premium and low grade. It doesn’t have its own tank.

Well......according to The Simpson's that's how it works (with Duff Beer), just relating my experience. Had to be INCREDIBLY coincidental though. Never had a problem except for when I used mid-grade. Had an incredibly loud backfire, then limp mode. Next day it was fine, never had the problem again. Put some octane boost and injector cleaner in tank. Vehicle had very low miles at the time.

 

[isis]

Well......according to The Simpson's that's how it works (with Duff Beer), just relating my experience. Had to be INCREDIBLY coincidental though. Never had a problem except for when I used mid-grade. Had an incredibly loud backfire, then limp mode. Next day it was fine, never had the problem again. Put some octane boost and injector cleaner in tank. Vehicle had very low miles at the time.

Coincidental. It’s been a while since I’ve worked at a gas station but next time you’re there ask how many tanks they have. I’m quite certain it’s regular, premium and diesel.

if you got a bum batch they probably have leaky under maintained tanks. Or it’s somewhere nobody uses premium and you’d have had the same problem if you got the high test.

 

[RustyNutz]

I did recently fill, but with 93 like always.
This is a video of the idle spark advance bobbling around, does yours do this? The random flashes of 10-16 dont seem right to me

 

[Donmatteo]

I’m guessing the tune doesn’t like your plugs