Car leans out after 29 min. of driving

[SPYDERGSTTUNER]

Ok so i searched and searched everywhere for clues or anyone having similar problems but mine just seems to be very unique . I start my car and let it warm up to normal operation temps before i drive, everything runs fine boosts great and car feels like it should. The problems start after about 20 min. of driving long distances, my car starts to lean out completely where the lights on my narrowband (wideband took a dump) dont even light up anymore. It doesnt feel like it affects it at all while this is going on if i keep driving at highway speeds. She boosts fine and it doesnt bogg or sputter or anything which just seems weird. When i get back into town after however long running lean on the highway the check engine comes on. When i come to a stop i press the clutch and my rpms drop to about 2-3k climbing slowly to normal rpms but staying lean. When i get going she sputters,backfires,misses,boggs doesnt boost past 10psi and sounds like a machine gun while in boost. I shut the car off for about and hour or so and everything goes back to normal until i get back on the highway and does it again. So far i have:

Replaced plugs went a step colder/hotter gapped correctly
Eliminated boost leaks
New wires
New Coils
Eliminated exhaust leaks
Eliminated vaccum leaks
Replaced MAF sensor
Replaced MAP sensor
Tuned and retuned to see if that would help or if tuner skipped/missed something

P.S. check engine codes P0455 and P0304 come up on the scanner.

 

[Mrdocprofessor]

with the symptoms you are showing it should be two different problems 1. check your gas cap it may need to be replaced also the same problem could be a vacuum leak.2. check o2 sensor cat. fuel filter and coil pack i know thats a lot but check it in that order and you should find your problem

 

[nightmares GS-T]

Ive had this issue before. Mine was my o2 sensor. Did the exact same thing drove fine for 15-18 miles then started acting stupid and going lean. If you have access to some sort of logger then check the o2 voltage when it starts acting up.

 

[eeeewidner]

Def check out the front o2 sensor.

 

[SPYDERGSTTUNER]

I just bought a new 02 sensor, a buddy of mine said the same thing. I've already checked for vacuum leaks as well as new coil packs, the fuel filter is not even 3 months old but ill recheck it, thanks for the advice everyone hopefully i figure it out quick im taking a 5 hour drive this weekend and dont wanna take any chances.

 

[Dhan]

Generally the O2 sensor lasts quite a while (+/- 50k miles) and are often working fine when ppl replace them.
However, they are very sensitive. The chemicals that generate the voltage that the ecu reads can be contaminated very easily. A car with a faulty O2 sensor may work decent at sea level but fail to even idle at altitude. We are at elevation, so a flawless O2 sensor reading is paramount.

You say you just replaced the sensor, are the wire leads perfectly intact, because it does sound like this is the cause of the problem.

 

[T is for TURBO]

If I'm not mistaken a failed or failing O2 sensor causes the car to go rich... not lean. Did you check for pre O2 sensor exhaust leaks by chance? If it's sucking in oxygen prior to the O2 sensor, it could cause it to read lean.

Sent from my T-Mobile G2 using Tapatalk

 

[SPYDERGSTTUNER]

Cant sleep thinking about what else to try anyways i did check the terminals and they are in perfect condition, i even used electrical connector cleaner to make sure dirt or any other particles dont keep the connector from making good solid contact. About the pre sensor sucking in air i dont know it doesnt quite sound right because as soon as the engine turns over shouldnt it be sucking air from the get go causing it to read lean right away instead of waiting 20-30 minutes to do so? Im might even go get me another sensor just to make sure this isnt a faulty one.

 

[nightmares GS-T]

If I'm not mistaken a failed or failing O2 sensor causes the car to go rich... not lean. Did you check for pre O2 sensor exhaust leaks by chance? If it's sucking in oxygen prior to the O2 sensor, it could cause it to read lean.

Sent from my T-Mobile G2 using Tapatalk

Faulty readings can cause it to go rich or lean depending on the reading. To the op use a logger to verify a bad o2 sensor instead of just replacing the sensor. Also note that when mine would go lean you could actually feel it in the car it would stutter for just a second. Does yours do that as well?

 

[SPYDERGSTTUNER]

Not that i recall as long as i stay on the highway driving 60+, is not till i slow back down or come to a complete stop that the car starts acting up

 

[nightmares GS-T]

Im not sure then. Mine would start acting up while cruising and I watched as the logger would show my o2 sensor going to 0.

 

[SPYDERGSTTUNER]

Yea this definitely has me puzzled as to why it started doing that, ill keep searching around maybe the wiring or some sensor gets too hot in the engine bay causing it to do this.Thanks for all the input everyone!

 

[SPYDERGSTTUNER]

Ok so i replaced the front 02 sensor and installed a new wideband and for whatever reason the problem went away. Id like to say exactly what fixed the issue but i honestly dont know which of the two fixed it

 

[DSMTyson]

I'm going to take a wild guess and say the wideband.

 

[lastshark08]

Has anyone thought of the coolant temp sensor? If your ecu doesnt know the temp of the engine it could do all type of crazy things. Are your fans running constantly?

 

[ECLIPSEESPILCE]

PO304 is a cylinder #4 misfire code. Move the cylinder 4 injector to a different location (example switch cyl #2 and Cyl #4 injectors) and see what code resets when the problem returns. Make sure codes are cleared before the test drive. If the problem moves replace the injector. The reason i suspect injector is based on previous ignition repairs listed. The same test could be done if you were to move two spark plug wires to two different locations.

 

[Droptop Spyda]

Is your wide band tied back to the ECU for control or just used for visual tuning?