Idled rough and ran poor now won't start

[NCSHOracer]

I have a 92 that has a 3.2 swap. Two days ago it started acting up and wouldn't want to run past 3000 rpms on the road. The car can act up when low on gas like 1/4 or less. My dad said it could do be moisture in the tank, and it been REALLY humid here. The fuel pump was replaced back in November. I checked fuel pressure and reads 40 while priming. I have the codes 511, 556, and 557. It was running perfect until now, what could be the problem???

 

[rubydist]

if in fact you have a 511 code, then the odds are 99.9% that you have a bad pcm.

 

[NCSHOracer]

Could an LPM chip cause the 511 code?

 

[NCSHOracer]

I just went out and it started right up and ran just as good as it has been. I let it get to temperature, and I checked the codes again and got a 511 and 542 which a 542 comes after a 556 has been present.

 

[kevinspann]

An LPM or Tweecer that isn't seated can cause issues like that. Not sure if it will cause the 511. Ford EEC IV have issues with capacitors going bad on the board too. Also not sure if those will cause a 511, but there's a chance...

 

[rubydist]

yeah, some of the chips will set a 511 _ I didn't realize you had a chip.

so, you could have a dis issue or a crank sensor issue - those are the most common causes of a "running poorly and dies when warm" type of symptom.

 

[pjtoledo]

humidity eh? if you had a northern car I would suspect moisture in a marginal or corroded connector someplace.

 

[pjtoledo]

I have a 92 that has a 3.2 swap. Two days ago it started acting up and wouldn't want to run past 3000 rpms on the road. The car can act up when low on gas like 1/4 or less. My dad said it could do be moisture in the tank, and it been REALLY humid here. The fuel pump was replaced back in November. I checked fuel pressure and reads 40 while priming. I have the codes 511, 556, and 557. It was running perfect until now, what could be the problem???

that reminds me of something.
quite a while ago when my 92 was only a few years old, on very hot & humid days like 90+ if the tank got below about 1/4 there would be really strong gas fumes. something about vapor pressure and the volume of air above the fluid, I think. simply filling the tank was a temporary fix, the real fix was cleaning the clogged restrictor tube in the vent line under the radiator.
not sure if its your problem, but cleaning a tube is easy & cheap.