I bought this used '97 Ranger (2.3l duratec, manual, 2wd) last December. After a month, the timing belt went out, and we got that (and the fuel pump, it was going bad) replaced by a shop.
About a week after that, my engine started behaving terribly: When I start it in the morning and drive it to work (hour or so of driving, 7-8ish AM) it performs fine usually, as the weather is cold during that time. Towards the early afternoon, as soon as the temperature outside hits anywhere above 60ish and when the engine is warm, she goes berserk on me - shaky idle, loss of power, slow acceleration, almost no acceleration uphill, and intermittent hard jerking/misfiring that makes it really hard to drive. The jerking is the worst part, but also hard to predict sometimes. It only jerks in warmer weather, when the engine reaches normal temperature, but under those circumstances, it seems to come and go randomly. It'll have a fit for five minutes, stop jerking for ten, then come back later. The jerking seems to happen regardless of how much the throttle is pressed, but it's worse when I floor it. It also seems to be worse/more likely when starting from a stop.
When the engine is warm and I let off the gas completely, it'll jerk once, start slowing down, then jerk again, and slow down even faster.
I have these error codes:
-Camshaft position sensor/circuit error-Egr flow insufficient
-Bank 1 lean code
I've been throwing parts at it for a while and the folks at o'reilly's know me by name. Here's what I've swapped:
Camshaft sensorCrankshaft sensor
Spark plugs (Don't worry, I bought OEM, gapped them properly)
PCV valve and grommet (idle improved quite a bit)
MAF sensor
Throttle position sensor (cleaned the throttle body as well)
Fuel filterI also ran a can of seafoam injector cleaner throughRecently had an oil change
I don't know if this makes a difference, but the previous owner also installed a short ram intake.
​​​​​intake. I've read that this could be a plug wire/ignition coil problem, so I might replace those as well.

At this point, I'm somewhat clueless. Any help would be greatly appreciated. I'm a bit short on money, so I'm trying to avoid another trip to the mechanic.

Thanks!