Hey guys. I own a 2003 Mazda B3000. When I first bought it, (170k) It idled beautifully, so beautifully I couldn’t feel the engine run most of the time. Now I’m at about to hit 175k and it idles like crap. I’ve already changed the spark plugs to Motorcraft plugs, changed the wires, camshaft syncronizer, oil pressure sensor, IAC Valve, valve cover gaskets as well as the PCV Valve. None of these recommended repairs have done anything except make my oil pressure sensor twitch even worse than before. My idle is somewhat worse as well, especially after highway drives. I’ve spent so much money on trying to fix this. I thought for sure that doing all of this maintenance would fix my issue someway or another.

would the oil pressure sensor “twitch” have something to do with the rough idle? My guess is yes but there’s some people out there that may say no.

All I want to do Is finally fix this rough idle. Any suggestions?

 

Rough running should first be diagnosed with compression test, that saves wasting money on non-fixes if its a compression issue
So I would do a compression test
cold engine
All spark plugs removed first
then test each cylinder and write down results
If one or two cylinders are 20%, or more, lower than the others then you found the problem, burnt exhaust valve(s)

No, on oil pressure "twitch" it might be a symptom of high and low RPMs with rough idle, but not a cause, computer doesn't "know" oil pressure

When people do spark plugs and wires they can mix up firing order on coil pack
Coil pack has 3 coils inside not 6
Spark plugs are fired in Pairs, 1/5, 2/6 and 3/4 are the Matched pairs

So on the coil pack you should see
3 4
2 6
1 5

2/6 will always be the center pair, and 1/5 3/4 at the ends, and if you reverse the ends then rough running for sure

And some wire it like this
3 6
2 5
1 4
Rough running for sure

Just a heads up, I have chased my tail when I KNEW the firing order was correct, bet money on it, shave my head if its wrong.................................
It was WRONG, lol
So after you have checked for the 5th time, have a friend check it 3 times, lol

 

Even new parts can be bad out of the box. That has caused me some issues in the past.

I would also look into vacuum leaks. Youtube a homemade smoke test kit for vacuum leaks. ( have not watched this particular one but should give you an idea) Vacuum leaks can cause all kinds of issues.