I bought a 1994 mazda B4000 a couple months ago with 124000 miles on it. It runs and drives great! The only problem is that when it is at opperating temps and cools down for 30 minutes or so it runs like crap for a minute or 2 and than clears itself up(unless it is cold outside). There is no check engine light or anything. I can tell you a whole lot of what isnt the problem like I have replaced the engine coolant temp sensor and the mass air flow sensor. And the spark plugs and wires are brand new. I have also disconected the vacum line going to the egr valve thinking that it could be sticking open and it still runs bad. Any suggestions would be great!

I have the same peoblem!