So I've got a 94 pickup with a 22re, and I'm having issues with hesitation and idling. It ran fine until my check engine light came on. The codes were for the EGR and O2 sensor. I replaced to o2 sensor, and just deleted the egr and air injection system. I unplugged the battery and no new codes were being thrown. Yet it was still running like garbage. I just barely finished replacing the pcv valve and ended up replacing my valve cover gaskets cause it was leaking a bit. But it seems the PCV valve wasn't the issue either. So I'm thinking maybe the TPS? Or MAS? I'm kinda stumped right now. I have a video that shows how its acting but its an mp4 so I can't upload it.
2ToyGuy
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Apr 12, 2026
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The FSM has test procedures for both the TPS and the MAF. Pretty easy. Just need a multimeter that can do ohms, and a feeler gauge set.
Make certain the big tube between the MAF and TPS doesn't have any air leaks to it. It's a pretty common problem, especially at the corner pieces. The flex pieces, the corrugated pieces. Pretty easy to check. Just look down the tube with one end blocked off, and flex the corner pieces around a bit. If there's an air leak, it can have some bad effects. Check the vacuum lines for leaks, cracks, etc. Check the vacuum ports for being clogged with whatever. Maybe a shot of carb cleaner down the vacuum ports might help.
Make sure the IAF, the valve that feeds extra air to the TPS while the engine is "cold", is working correctly. The one that has the fairly large air tube coming up to the TPS from below. If it's not opening, or closing, properly, it can be a problem.
Finally, check the o-ring on the Idle Adjust Screw. They get old, and can crack off pieces. If there's a piece or two down in the air passages it controls, or even if the air passages are dirty enough, the idle will always have trouble. If you remove the Idle Adjust Screw to replace the o-ring, a short shot of carb cleaner down the air passages can work wonders. The o-ring is a very small, very common size, that can be found in auto parts stores, Harbor Freight, and so forth. Make sure you put a thin layer of Vaseline, or silicone dielectric grease, on the new o-ring, if you do replace it. It makes it last a lot longer, and seal better.
Good luck, and keep us up to date on how things are going for you
Pat☺
Make certain the big tube between the MAF and TPS doesn't have any air leaks to it. It's a pretty common problem, especially at the corner pieces. The flex pieces, the corrugated pieces. Pretty easy to check. Just look down the tube with one end blocked off, and flex the corner pieces around a bit. If there's an air leak, it can have some bad effects. Check the vacuum lines for leaks, cracks, etc. Check the vacuum ports for being clogged with whatever. Maybe a shot of carb cleaner down the vacuum ports might help.
Make sure the IAF, the valve that feeds extra air to the TPS while the engine is "cold", is working correctly. The one that has the fairly large air tube coming up to the TPS from below. If it's not opening, or closing, properly, it can be a problem.
Finally, check the o-ring on the Idle Adjust Screw. They get old, and can crack off pieces. If there's a piece or two down in the air passages it controls, or even if the air passages are dirty enough, the idle will always have trouble. If you remove the Idle Adjust Screw to replace the o-ring, a short shot of carb cleaner down the air passages can work wonders. The o-ring is a very small, very common size, that can be found in auto parts stores, Harbor Freight, and so forth. Make sure you put a thin layer of Vaseline, or silicone dielectric grease, on the new o-ring, if you do replace it. It makes it last a lot longer, and seal better.
Good luck, and keep us up to date on how things are going for you
Pat☺
