Hi

I bought a 1994 toyota pickup 22RE (ODOMETER: 257445) 5 speed manual a few months back for around $500. I am the now the 3rd owner. Was a farm truck most of its life.and I'm having a slight miss fire after engine has warmed up. I replaced the sparkplugs but I didn't check the gap. Installed new wires and cap and rotor. I also replaced my heated o2 sensor since my check engine light went on for it. Not sure what to do next to fix it. Any ideas?

will attach photo once I'm up for the day.
Other maintenance Ive done is replace the valve cover gasket.

Other issues:
makes a metal on metal sound from transmission when in 4th gear at speeds around 40-47 and in 5th at 45-52.

 

Check your valve adjustment. A tight valve can cause a little "blip" or miss you can notice at idle. Do a compression test if you have the tool. Vacuum gauge test can tell you a lot. Watch some youtube videos.

A metal on metal sound can't be good. Pull the transmission drain plug and see if you have any metal pieces come out. A fine fuzz is normal. Anything larger and it's time to repair or replace. U-joints can make it seem like the noise is in the trans at times. You should check them anyway. Loose sloppy U-joints are easy to find but, a seized U-joint is easy to miss.

Now is a good time to do the same with the T-case ,differentials and engine as well. Change oil and check for any metal. Plastic pieces from timing chain guides in engine oil. Just to see where you're at with this new to you truck.

Timing chains and guides are trouble on these engines when they get a lot of miles on them. You can look down in at them (somewhat) when you have the valve cover off.

Good luck with your truck.