Question

'98 S-10 with 96,000 miles. Was running fine then all of a sudden it stalled. It has run bad ever since. Runs good for a little while until it gets to operating temp. It has to sit long enough to cool down before it will run right again. The cooler it is outside the longer it takes to start running bad. It will run ok at speed and excelerating but not at idle. When it's running bad it stalls when I come to a stop. Some bucking and jerking at low speeds and RPMs after it starts to act up. Seems to be a dead spot in the throttle after it starts running bad. Two codes have been given. One is "System To Lean" and the other is EGR "Insufficient Air Flow". Was told to take EGR valve/sensor and make sure that it's not built up with carbon inside. It looks good. Nothing that would restrict airflow. Little plunger seems to work properly. Have replaced fuel filter, catalytic converter and plugs. Have cleaned butterfly inside throttle body. What ever it is seems to be temp. sensative. The hotter it is outside the sooner it runs bad and worse it is. Getting ready to start replacing sensors. Coolant temp. sensor and o2 sensors before and after cat. converter then EGR valve. Is there anything I'm leaving out or you might suggest before I spend all of this money because I'm running out of options.