2.4 miss at idle

[meandmit]

My MM has had a crazy miss at idle since I purchased it. I've done all the usual things, plugs, wires, cap and rotor, fuel filter, cleaned valve body and even run a tank of injector cleaner through tank with no difference. Today I installed new injectors, still have same weird idle miss...but now gained a little hesitation right off idle. It took a while to get the computer to figure out the idle after the battery reconnect. The truck has 109,000 miles on it and is a '94. What should I do or look for next. Compression or leak down test. Think it is a valve? Its idling at 800 rpm in video.

https://youtu.be/dxoFvMYFbBg?si=ySljmFIhzZ5m1FKy

[xboxrox]

Testing with a vacuum gauge ? I only know that an engine should have good vacuum 'n steady needle reading... I think it can detect vacuum leaks or valve leak..?

[meandmit]

Well tested compression, 180 on 1, 2, 4 and 150 on #3. Timing was 10 btdc, but would dip down to 5 then back up. Vacuum shows a steady 18 at warm idle.

[meandmit]

Ok, rechecked compression hot and all is well
#1 198
#2 192
#3 190
#4 195

[dash]

if you know which cylinder, fiddle with that injector connector/wiring

[xboxrox]

Have you used a spark plug tester or a real spark plug to visually witness good spark at the plug gap? Some YouTube videos even demonstrate finding sparks going to ground and not to the plug caused by spark plug wires that vibrate move wiggle etc ~ they test at night or in a darkened area...

Hope the fix is quick & cheap ~ good luck...

[EL.95MAX]

had the same problem ur going through r now..did everything u did to... and goes to find out it was inside the injector harness ..the injection harness kept rubbing on the valve cover ...hope u find the problem

[meandmit]

So I reinstalled the old oem injectors with new seals, the new ones I installed from Rockauto are junk China stuff. They came apart taking them out, had to fish the filter screens out of the fuel rail....So after i re-installed the old ones the idle came back, no up and down, up and down...no hesitation either. Still have the miss at idle though. I did fiddle with the idle screw and drivability is a whole lot better, idles at 800rpm and when compressor kicks on 1100rpm.