Engine stall after throttle input in P, rpm's sustained in D/R? WTH?

So lately I noticed that my tundra's engine has been hesitant to start after few minutes of running. It'll accelerate fine with no misfires or stalls and you would never know there is a problem while driving. Also no check lights. BUT, after first start, after a minute or so while at idle, rpm's are low (not sure what normal idle rpm's are) but seems pretty low. Around 400 rpm's. Put it in drive and while moving in low speed like as if I'm parking, I literally have to ride the brake with left foot while giving it gas to prevent it from dying as soon as I put it in D or R while moving slowly. Once I get going though, runs fine. Now, I stop, put in Park and it'll sometimes idle, barely and diming the headlights, but if I give it a light throttle input, rpm's rise normally and then it'll die. Restart can take a few cycles. Once started and rpm's barely sustained, give it a little throttle and it'll die right away.

So far per Hayne's manual trouble shooting, I can hear the fuel pump relay click, throttle control motor seems to do it's job moving the throttle body air valve, I can hear fuel flow in the fuel rail and also the fuel pressure indicator popped up is up as indicated when there is pressure. I've not put a fuel pressure gauge on yet and doing electrical ohms tests are supposed to be done at 60F ambient temp or above and it's 18F in my garage (not sure what effect that has on ohms checks). I elected to change out the fuel pump and fuel filter so far. The throttle body is a bit dirty and figured it needs cleaning but I doubt that is the culprit. Any suggestions?

Thanks,

 

Just out of curiosity....what is your climate control set at?

In defrost, or defrost mix, the AC automatically runs. Normally engine RPM varies as the AC turns on an off as the AC uses a not insignificant amount of power at idle speeds.

Just to rule it out...maybe check it with the AC off or disabled, in case the AC unit is starting to seize up and causing enough drag to kill the engine at idle when it kicks in.

Probably not it, just worth checking. Other than that...someone above my pay grade can hopefully help you. I'd certainly clean that throttle body too.

I would hold off on the fuel pump as its kinda a sucky job to do just to rule things out and is more likely a problem at high RPMs than it would be at idle. Honestly, maybe the last thing you do after you've ruled everything else out.

 

Well, bit late for the fuel pump. lol! I changed it because with it being 19 years old and 240K miles, I was already going to do a refresh on all sensors and pumps (except the oil pump) to give it a refresh. But since we're on the subject, I had made sure that the A/C and fan/EVAC was all off since I wanted to make sure the A/C pump didn't drag it. I have the feeling, and that's just based on a hunch, not knowledge as I'm not a certified SAE mechanic but other mechanical knowledge, I'm getting the feeling it's somehow getting starved of fuel but I could also be completely wrong here. lol! Cars are such a pain in the ass.

 

Clean the throttle body 1st.

 

Check all of the vacuum lines. Idle issues are often vacuum related.

 

+1

And the MAF sensor while you're at it. Do one at a time, then test how the engine runs. That way if it fixes your problem, you know which one did the trick. (But it will probably be the throttle body.)