I'm new here as you can tell but I hope to stick around and help out.
My dad picked up a used 1999 Mazda B2500 which has a 2.5L inline,
4 cylinder (8 spark plug design).
The engine idles rough, and stalls if the throttle is blipped and allowed
to return to idle. The engine in general lacks power overall.
We started by checking some vitals, and then replaced all eight spark plugs,
wires, PCV valve and all fuel injectors since the intake was off anyway.
Here are the measurements and info:
Fuel pressure at idle 70 PSI
Compression Cylinders 1-4:
198, 202, 200, 210 PSI
No DTC codes present
Plug appearance seems fine on all cylinders
02 Sensor #1 swings from 110 mV to 880 mV
02 Sensor #2 swings from 100 mV to 800 mV, and then flat lines once warm
Short term fuel trims are +10%
Long term fuel trim is 0.8%
My next step is to check the EGR valve, vacuum lines for cracks/loose fitting, and the IAC valve.
They all looked fine, but I'll have to double check everything as the tune-up improved nothing.
If anyone is aware of a notorious issue with this motor, please post
some tips and info as we're running out of things to check.
In the mean time, I'll search more threads for answers. Still nothing