Can someone please tell me what these readings mean ? I've got trouble codes p0171 & p0174 and at the time of check engine light data 8s as follows(sorry if I misspell its a cheap obd2 reader from wally world
fuel 1& 2 -CL
LOAD- 25.5
ETC(F)-207
SHRT FT1- 1.6
LONG F51-23.4
SHRTFT2-9.4
LONGFT2- 29.7
MAP (InHg)- 12.4
RPM- 707
VSS- 14
CATEMP1-11190.20
#2- 10190.40
VPWR-14.244
ABS-24
EGR AT- .999
SPARK ADV.-17
IAT-99
MAF-1.033
TP- 22.0
EVAP%-30.2
FLI- 0.4
EVAP(IN H20)-0.877
BARO- 29.5
TPR-8.2
AAT- 86
TPB- 21.6
APP.D- 18.8
APP E- 9.4
TAC PCT- 12.2
I replaced vave cover gaskets and oil pan gasket right before these trouble codes so since then I cleaned maf sensor &throttle body, plugs and wires and repaired 1 vacuum leak its now idling much better and so I cleared the check engine light .

 

you need to find out at what engine rpm the code set.
monitor your fuel trim at idle and 2500 rpm....post the fuel trim for both banks at both speeds.

 

try this video


If you try the starting fluid have an extinguisher handy. Safer to use stoddard pain thinner in a spray bottle.

 

its called false air entry. this can be ruled out in seconds by viewing fuel trim data. if its adding fuel at idle but normal at 2500...you have a vacuum leak/false air entry. if its adding at both rpm there is no vacuum leak... you need to check the fuel pressure.

 

Ok the last thing I did was replace a split hose connector on one of the lines going into the rear of the driver side valve cover which brought the idle back down and got it running alittle better so I cleared the check engine light however, it is still having some issue because the rpms are still jumping, not real drastic but enough that I know there's still a possible value leak. The check engine light hasn't come back on yet but I know its just a matter of time and it will. One thing I've noticed this morning is my battery dial is reading lower than normal so im about to go test it. Ive alo had during this whole time is the service stabilitrak light has come on and off several times. Not sure what thats about because that could be any number of things. One other thing when I was putting the oil pan back up one of the long bo.ts at the bottom rear snapped off . Would that be causing me problems ? I have no oil leaking and even though I know I need to replace it can it wait till I change the oil again?

 

What should th readings be on the fuel trim data so I can tell if its adding or not

 

were there any misfire codes p0300 p03001 to p0308? if you have misfires...fuel trim is meaningless
f uel trim should be from 0 to +/-10%
+ numbers. ie +20 the fuel is lean so its adding fuel. - numbers the fuel trim is rich so its reducing fuel if its +/- 19 or more its at the adaptive limit.

 

There have been no other codes except the first time the check engine light came on there was a 7ea code 0521 oil pressure sensor/switch range. I ended up clearing the codes and the next time the check engine light came on it wasn't there. The light still hasn't come back on but it is still running horribly and seems to be getting worse. My oil pressure keeps dropping and going up in sync with the rpms and my voltage ,eels dropping and rising and the battery tested fine . Today I get to inspect front wheels cause all of a sudden the wheels are making symptoms of failed bearings which I replaced only 6mo. Ago with Timken bearings.did new rotors and pads too. By the way this tru k just turned over 300k 2wks ago you wouldn't think it if you saw it and I just had the rear end worked on. Oh and did the suspension front and rear a year ago. So now the engine ...im about ready to pull my hair out lol

 

Your scan tool should at least display a + or - in front of the fuel trim. If it’s only displaying one, assume the lack of a symbol is the opposite of the symbol that’s displayed (ex. if you only see - then no symbol would be positive)

Catching random bits of advice is one of the reasons I’m on these boards. Sometimes the simplest things are the easiest to overlook.

Thanks for a genuine “ Well duh!” forehead slapping moment - I’ve been seeing a lot of customer cars with system lean codes and not all of them have had obvious causes. I’m definitely going to remember this tip - it’s easy for me to start overthinking things.

 

i got it from motor magazine. they pointed out...there is little or no manifold vacuum at 2500 rpm.