Hi guys, I all of a sudden noticed 3 problems with my engine that suddenly cropped up, all within a day.

1.) I got a check engine light code for the front right heated O2 sensor

2.) The car cranks on the starter for a while trying to start and when it does start it really sputters around 400RPM or so then fires up to life, this happens hot and cold, but I have noticed it more when the engine is hot

3.) When driving if I give it approximately 1/4 throttle, no more, no less, I hear an intake hiss. If this was a vacuum leak wouldn't I hear it the most at idle when vacuum pressure is the highest? I checked my vacuum hoses, they all seem to be ok.

I have a feeling all of this is related somehow and maybe it isn't my o2 sensor but something else that is wrong with the system that is confusing it into thinking it is my o2 sensor?

Thanks a bunch

 

Not really engine problems. But here you go.

O2 sensor: Get it fixed.

Start-up problem: Clean TB & IACV

Intake hiss: Normal. Mine has hissed in different situations, stock intake / aftermarket, etc.

 

holy **** this sounds like my mystery starting issue.

only happens when the engine is hot tho....

i was throwing a code for a rear o2 sensor, but i got a simulator and now the CEL is gone (so far)

wtf>

 

Here's the thing though, the car started up pretty normal before I cleaned the TB and IACV, after I cleaned the TB and IACV everything idled perfectly and the car would fire up instantly, like it wasn't even funny how quickly and easily it started. It was perfectly fine for a few weeks, now all of a sudden all 3 problems hit me...and at the same time.

 

Try turning the key on and waiting a second before you actually start it. This lets the fuel pump build up fuel pressure before you crank the motor.

 

only if its an injector issue.

ive tried that for my warm starts and it makes no difference.

 

Forgot he was having mostly warm start problems...

In the case of cold starts (i.e. the car sits all night or for a couple days) the car would not hold fuel pressure, hence the need to "prime." I didn't think this was an "injector issue." I had this problem before and had no injector problems....



to the OP: Did you replace the gaskets when you cleaned the TB and IACV? Are there any vacuum leaks anywhere?

 

Not an injector problem. Mine starts better when I prime the pump, and my injectors are fine.

It helps when the fuel level is low.

 

i gotta try that my self but my car misses like the clutch is slipping but i got a new clutch on it and i know its doesnt slip at all it only happens in 2nd and 3rd gear. could a bad knock sensor cause this, cuz its been giving me knock sensor codes

 

From my point of view,its the vacum leak.Have it checked out,or check it out yourself.maybe take te stock intake off,then search for small cracks or leaks or holes.

 

1. Fix the O2 sensor

2. Check your crankshaft position sensor, the reference one by your pulley. I had the same issue a little while ago, you can find the test in the FSM, or let me know if you need it otherwise. Replace that if you find it is bad. Also check the harness and ground for the circuit as that would indicate a bad CPS also.

3. Your throttle noise is nothing to worry about. Do you by any chance have a short ram intake? It is very apparent when you have a short ram and is caused by the throttle butterfly valve creating an increase in airspeed right at the throttle valve because of the smaller area that it has to travel through.

Hope this helps.