So I’m currently still in a race to figure out what’s going on. Car having trouble during warm starts. Rough idle. Engine rocking side to side. Not too pressed about that, but having the difficulty starting makes me keep feeling like a woman in a horror movie Seeing if anyone has had this issue.

Right now, I’m contemplating doing a fuel pressure regulator replacement, but after having codes scanned...it doesn’t seem like that may be necessary (which would involve removing plenum). Thing is, I already bought the part, but considering returning it because it sounds like it may be an intake air sensor.

However, the lean system code leads me to believe it could be the pressure regulator, but I’ve also read up on some things about intake leaks and such.

I have to say one thing that may or may not be coincidental: I thought I had cured the warm start issue by adding a sea foam type of additive to my oil and gas tank. This cured it for a few weeks. I added it again, and it went away again...for a few weeks. So far I have only added it to gas tank since. But lately it’s been everytime I try to start the car when it’s warm (as in not sitting overnight), it’s a struggle. I’m contemplating draining my newly changed oil, and adding it again. I don’t know if it’s the can of Restore 8 cylinder formula that I used during my oil change that’s causing it, or what.

I’m at the point where I’ve already done fuel filter, both coolant temp sensors, new gas cap, cleaned maf and IAT today. At my wits end. Does the fuel pressure regulator actually throw a specific code, or would a broad code point to it as a possible issue? Removing the plenum to get to it, seems like an awful project.

Look at ec-31 in the service manual. Follow the intake air temp code first. Ec-235 for the lean code.

Thankyou...I was looking at that the other day and printed up the fuel pressure sensor instructions. But now that I’m thinking about it, that might not be it...which is good because I almost ordered an OEM plenum gasket, which I have 0 time to do this week.

For the time being, I brought a Intake air sensor and going to see if that helps.

On your P0110, while it's possible for the sensor to fail, it takes a hard failure to trip the code. If the sensor is off by a few ohms, the ECU will never know it.
My point is: check the little harness that goes to the IAT sensor. It gets a lot of stress on it, particularly right where the harness goes into the connector on the IAT sensor. I'm guessing you have a broken wire there.

Well I’ve checked and fixed that wire before. Doesn’t seem like it has broken sense. When I put the new one on, I’ll take a look at both

The main immediate issue is having to crank the engine 3-4 times and press the gas while I’m doing it in order to get it to fire up. This is not good.

Update: replaced sensor, and air filter but nothing changed. I’ll go ahead and keep it, but still narrowing down. I noticed a little bit better starting today (versus me cranking it 5 or 6 times and getting NO start, while seeing white smoke blow out the tailpipe). Replaced 4 out of 8 plugs (stuck boots), I’m suspecting the 22,000 miles on ngk v power might of burnt them up.

Just did oil change, suspecting maybe some additive contamination. Will see in the morning if starting up will be easier. God help me.

Update: no real change. Starts okay first thing, (though it used to fire up as soon as I turned the key, after sitting overnight).

Now, I feel like a damsel in a horror movie everytime I try to start after sitting more than 30 seconds