Hi-
As I have mentioned before hun, this is very common and developmental. I did say mine didn't get longer naps until the 5/6 mth range as well. You also had mentioned to me you are unable to resettle naps and it can be tough with other siblings at home.
I too remember having a difficult time around that age. It's just easier when they can handle longer A times hun. For now, as I had told you before- anyway you can get baby to sleep, just go for it. He needs the rest and if it means going out for car rides, wearing him, taking him out on a stroll then by all means!
I remember purposely making sure I left the house and stayed out JUST to avoid even doing any naps at home. It was extra work I was over doing and it was always just stressful. Especially as the day went on the naps were always a tad more difficult.
As Lindsay said, and I had mentioned to you as well, try and stick to the "AVERAGE" A times as best as you can. It's frustrating to say the least! I hear ya! I was just there a few months ago. But the best solution is just getting out and about... napping on the go. My thing was to try and get at least the morning nap at home, in his crib (I started doing naps in his crib around 3.5 mths if I remember correctly. One at a time) ...since it is the most restorative. If I could I would try for nap 2 also but I PURPOSELY left the house after that. I did not want to handle or deal with naps
haha! It really helped.
Hugs! Xo