Thread: P0171 Code LTFT Maxed @ Idle

Well a little update. I tried reinstalling the rear o2. Nothing different.

So, I got in the engine bay and put Zipties on EVERY vacuum hose where the hose goes on the nipple. Now keep In mind I didn't have any leaks according to brakleen and propane. But........
My STFT's and my LTFT's are back at 0
+/- 3....... Guess I had a leak at one of the lines that didn't show its face to the torture I put it through. But leaked just enough to screw up my fuel trims.

I'm a little in the negatives but that doesn't concern me unless they go farther than 6%.

I still don't know which line was leaking.
Don't forget the brake booster hose

I haven't had any luck either now instead of locking in at zero at wot its going to 12.5 but while cruising up to speed it'll be at 5.6.

Mine is actually starting to act up again. I'm in the process of getting my PCM checked by reptile. I'll let you know my findings.

Cool thanks, hey by any chance do you know what pin to bend to put the fuel pump on high mode all the time?

Sure do. Lower left pin on top left relay.

Ok cool thanks, cause my ltft are lower while normal accelerating but jump up when wot to like 8.0. Have you guys checked if your evap is stuck open?

That's something I haven't checked.
I need to take a look at that when I get home today.
I borrowed a Fogger from a friend of mine but it took a dump last night.
Didn't even have time to use it.
Might be down for driving to chattanooga for a day of diagnosis! Lol

I think I may have to get a fog machine and try again, this code really is a pain in the ass haha anyone getting slight kr spikes while driving?

Damn right it is! Haha

Not while cruising. That sounds like false KR. You may have something rattling under the car causing that.

Well it'll jump up to like 8* sometimes when my car doesn't want to shift to third because of that skip shift tune so it wants to stay in second. And sometimes when I get on it it'll jump but never stays if I let of and go again it'll read 0* maybe its cause I'm running straight headers right now and everything rattles lol, def need exhaust finish soon.

I'm not, I think if its stuck open it'll pull vacuum through but I can't find the post I seen.

Ok, been doing some more testing.
I actually just snugged down my TB bolts a little extra. And checked all of my LIM and SC bolts to make sure they were Tight.
Now when I'm cruising or idling the ST &LT trims are fine, But......
When I let off the throttle the LTFT'S spike to +16.4 until I either come to a stop or give it throttle!????
Now I'm lost for sure! Lmao

I've been in contact with brian about another PCM and should have one on the way shortly. I'll post up my findings once I get it swapped in.

Currently I actually have a similar issue. Sort of waiting for someone to look at my tune to see whats going on. That and I plan on doing heads/e85 soon so Im not overly worried about it right now. But with mine...

Runs great cold/warm. Totally normal LTFTs. Tons of power (spin tires at 50mph type power).

Once it gets to full temp (180-195) for a minute it goes to hell. Massive drop in power and my LTFTs are 16.4 at idle and as soon as you give it any gas it goes like -19. Cruising LTFT is also adding tons of fuel.

Also at idle when its adding tons of fuel you can smell fuel strongly through the air vents. Do you get that? No one can find any vac leaks. No trouble codes.

Its almost like my PCM goes into a different tune mode when it gets to full temp... I've been watching this thread to see what your solutions are to see if I can try them too.