OK !
First off, I am assuming from your posts that you are young and that you live at home with your parents. Second, I try to be gentle, but I sometimes speak too bluntly for some people, although I mean them no disrespect. Third, the reason that I am here and try to answer questions is because of the birds and only the birds, they need all the help that they can get. Fourth and lastly, Feel free at anytime to tell me if you disagree or even if you feel that I am too blunt or just totally wrong. I don't get offended and will still always try my best to give you the right answers.
With that out of the way I feel like we can continue on with equal footing.
You are at present not helping yourself or your bird to having a good relationship or life together. The only possible explanation for this that I can think of is that you simply don't yet have the knowledge or experience that you need, so I will begin there, after we finish with your current problem.
So based on what you have said , I am thinking that this truck is not operating correctly and that its problem, at least as it may be affecting your bird, is either in its fuel system or in its exhaust system causing it to give of fumes that are making your bird deathly ill and if you continue to take him out in this truck your bird will die soon. The truck needs repair before your bird can be allowed back in it. Also try to get your bird a check up as soon as possible with an avian vet, not a regular vet , an avian vet. The damage to your birds respiratory system could be quite severe as they are much more sensitive to such things than we are and it may take weeks to fully realize how much damage has occurred to him.
In addition to fumes from cars and trucks there are also many things in your home that could injure or kill your little friend that you should be aware of, so I am providing you with a link that on its second page contains a list of things, plant, woods, foods and household items that are good for or are toxic to your bird. Please take the time to read it, it is very important to the well being of your bird.
viewtopic.php?f=8&t=12521 Let us now look at your little friends diet and for this I am providing a list of food as recommended by The World Parrot Trust for this species of parrot.
Diet:
Fruits such as: apple, pear, banana, cactus fruits, pomegranate, forming about 30 percent of diet; vegetables such as: carrot, celery, green beans and peas in the pod; fresh corn; green leaves such as: Swiss chard, lettuce, sowthistle, dandelion, chickweed; spray millet; small seed mix such as: canary, millet and smaller amounts of oats, buckwheat and safflower; soaked and sprouted sunflower seed; cooked beans and pulses and boiled maize; limited cubed hard cheese; complete pellet
Use this list as a basic guideline on what your bird needs as there is room for a lot of variables and as long as you get the percentage of the food types right and use only bird safe foods from the list in the link you will do fine with his food. Your bird needs to be fed breakfast shortly after sunrise, right now that is between 6 and 7 am. My birds get their breakfast, I use a cooked mix of white beans whole grains, mixed vegetables and fruits. I make this once a week and freeze half of it for the second half of the week, when I serve it I usually add a couple of fresh raw vegetables such as squash and carrot and peas and some chili powder or basil and one fresh raw fruit. I like to give them some fresh greens such as kale and dandelion and some fruit, it depends on what I have right now I have blue berries, to nibble on through the rest of the day. Then for dinner I give them their seed mix and remove it after they go to sleep. In your case a couple of teaspoons of your seed mix should be plenty.
Your bird needs to get the light from both dawn and dusk in order to keep its endocrine system tuned to the correct time of the year and should get up and go to bed with the sun.
You mentioned that when you take your bird out to the market that you have him on your shoulder so I am really hoping that you are using an aviator harness on him when you do this be cause if you are not you are taking a big chance of losing your bird. If your bird is to be any place outside he should either be in a cage or wearing an aviator harness or you are going to lose him. That being said I really see no reason for him to go anywhere at his age except to see the vet. Your bird needs to have at least one or two hours each day one on one interaction with you and at least four hours of out of cage time each day to hang out with you, wander about exploring, fly or just play with his toys. Right now the majority of your time should be spent with bonding activities with him and then after a couple of months of bonding and getting to know each other you can begin to start training him.