Ive basically gone through everything. My 90 m20 starts up great and runs for about 3 minutes while cold nice and steady. But as soon as it warms up it starts going rough almost like its missing. Looking for any suggestions ICV is new along with distributor and cap. 17lbs, valves just done, alt at 13.9 .......o2 not to long ago tbs engages. . i dunno. .
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90 m20is -
Have you smoke-tested the intake yet? Vacuum leaks cause weird idle. Hard to detect one is the intake manifold gaskets. -
Ive hit it all with brake cleaner to no avail. I was reading about the penny trick. I dont see why it would work but im open to anything.90 m20isComment
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Well once it warms up the o2 sensor takes over. So if it runs fine when it's cold I would suspect that. And what do you mean by 17lbs? Are you talking injectors? Stock is 14.5...so 17 are too big without a chip.Comment
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i swapped in 17 hoping they would be in better shape and fix the problem90 m20isComment
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o2 was done fairly recently, if i unplug it will will it smoothout as a tell tell90 m20isComment
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The first action should be to have a smoke test run on the intake and fix the leaks it finds and the second action would be to have the original injectors cleaned and tested and then re-install them. Follow that with a new set of ignition wires, distributor cap, rotor and a set of NGK ZGR5A plugs. You'll also need to check rail fuel pressure and make sure it is in spec. There are other possibilities, but that is the place to start.The car makes it possible, but the driver makes it happen.
Jim Levie, Huntsville, ALComment
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the O2 sensor actually starts working immediately after it heats up - which takes 10-30 seconds. That's why it has a built in heater. Coolant temp doesn't need to be fully warm.
and if you have modified injectors but no software to go with it, get the stock ones reconditioned and put them back in until you can get a chip that supports them.Comment
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