03 Ram problems

Have a 03 Dodge ram 5.7 that was running great until last week and had a small backfire and started missing. Got it home and hooked a OBDII scanner to it and it said I had a misfire, misfire in cylinder 6, O2 sensor bad and crankshaft sensor. Check plugs and they need replaced so I changed all plugs and swapped the coil pack with the one on cylinder 4 and changed the crankshaft sensor. Still has a terrible miss and won't run but just O2 related codes. While working on it and trying to get it to run I got the flashing lightning bolt. Had cleaned throttle body about 2 weeks prior to this happening. I removed and cleaned completely and lightning bolt gone but still won't run right. Tried to drive to shop to get checkout today and when I hit the hard top I noticed my brakes didn't work. I went about a mile and it hit limp mode and red lightning bolt. Restart no lightning bolt and here I am now talking to you. OBDII gave 2 codes.P0038 and P0306 is all I'm getting right now. Plugs were not smashed just need replaced since they have 195k on them. I need help bad.

Your brakes didn't work at all? Did you spray anything in the TB motor (black housing on the side) when you cleaned it, it's been known to kill them if they get sprayed with something and it gets inside.

The brake pedal was like the truck wasn't even running and to my knowledge I never sprayed anything on the TB motor.

Fixed the brake problem. Apparently I unhooked a vacuum hose while removing plugs.

did that fix the other issues as well?

It sounds like it might be a broken valve spring. I had it happen on my 03 and it ran like crap and threw o2 codes I assume because it was running so poorly.

I haven't tried to drive it yet to see if the red lightning bolt comes on but I do have brakes. I will try to get it to shop today or tomorrow to get it checked. I had this same problem at 90k miles and a piston kept smashing my plug and ended up cracking a piston and had to replace block. Found broke valve spring when I got heads shaved and cleaned up.

Valve spring broke and to top it off I broke 2 bolts taking valve cover off. Neighbor says my rings are wearing out and I will need a motor soon.