i have a b18b1 that doesn't run properly when something in the engine bay reaches a certain temperature... the issue is, im not sure what it is...

The car will run fine on cold starts, and if it has enough time to cool down after its turned off, itll run fine when its turned back on. But if the car sits for a little bit, and everything gets heat soaked, it wont run right.

Here are the symptoms: at idle my tachometer will show the engine surging between 750 rpm to below 250 rpm (im sure my tach isnt that accurate), the hotter the engine bay gets, the lower the rpm's get. My air to fuel on my wide band AEM gauge shows dashes, air/fuel ratio is above 17. Engine shakes bad when accelerating, but keeping a constant speed is alright, feels smoother in higher rpm's.

If i go down the highway on a cool day when the engine isnt function properly i may be able to get it to run normal, i assume its the cool air replacing the hot air in my engine bay.

No CEL

Things ive replaced/upgraded hoping for fix:
Valve cover gasket
Spark plugs
spark plug wires
Distributor
MSD External coil
ECT Sensor

(unrelated) The gas tank has been replaced.

On Sunday, 4/7/2013 i ran a live diagnostic of my car before the issue occurs and while the issue is occurring... ill post the data, im not entirely sure what im looking at though, i think my map (maf?) sensor could be bad... i would greatly appreciate help or insight on the issue, thank you.

The document, Before, is before the issue begins:

The document, After, is while the issue is occurring:


at the moment i cant attach the spreadsheets, ill have to try later...

 

any suggestions, ideas, or advice? thanks in advance.

 

Your Lambda sensor output is pegged full lean. A worn out Lambda sensor will provide a lean reading. This would cause the ECU to richen the mixture when it is trying to operate closed loop.

 

Have you adjusted your valves recently

 

i have not adjusted my valves, and the o2 sensor is turned off in the tune... i think the issue may be the IACV, i purchased one yesterday so it should be here monday or tuesday ill post any changes if they occur... i appreciate the responses, by the way.

 

I had that issue on the stock ecu, but after I turbo'd it (obviously new tune) the problem went away....

 

i wish i had a decent import tuner that didnt live 3 hours or more away >.<... i changed the iacv and it didnt fix my problem...

@stowne78 did you have any idea what the problem was? and were all of your symptoms the same as mine?

 

maybe your ecu is going out?

 

my brother and i thought it may have been a bad injector the day my dad offered to take the car to a mechanic as a graduation gift, so we dropped the car off at a shop, fixed some minor issues and confirmed what my brother and i thought, it was indeed a bad fuel injector