FinallyOffRoad

I'm really stumped on this one. I just got this '88 4Runner a couple weeks ago and since then I haven't been able to figure anything out about what's wrong with it. I've replace the fuel filter, spark plugs, plug wires, oil pressure sensor, and thermostat. The last two were just because the previous owner left new ones, so I replaced them just because. Anyway, sometimes when I first start it up, it'll rev perfectly fine all the way up to as high as I push the pedal, but most times it just goes up and stops at 2000RPMS. One night, I drove it around for the fun of it, even though it wasn't revving right and then I let it sit running for about 45 minutes and after that it ran just fine. Next morning, start it up, which always takes quite a few tries to get it to catch, and it's doing the same thing as before. I also discovered today that if I rev it up really slowly, it'll rev just about all the way up and hold. Any ideas? Sorry for so much info, I just want you to know everything I know in case there's some specific detail that might be a red flag to anyone.

DCMatt

Check your fuel pump/pressure. Just because you hear the pump running doesn't mean it is providing enough pressure to run the engine properly.

I also have an '88. Mine would start and idle fine but if I put it in gear (auto trans) and try to move it would die. Parked it would only idle up to @ 2000 or so and die if if I pushed it higher. I put a new fuel pump on and the problem is fixed.

I suggest you get a guage and check the pressure before you spend money and effort on the pump.

FinallyOffRoad

Thank you! That actually confirmed my thoughts on it being the fuel pressure. That would make a lot of sense as to why it won't rev when I step on, but it'll rev if I hold it slowly and it has time to build up the pressure. Could you give me specifics on what gauge to buy and how to do it? I've never done anything like that.

FinallyOffRoad

I fixed this problem with a new fuel pump. It works great now. Thanks!

scope103

Did you get the pressure gauge? Details, and maybe photos of your attachment, would be nice.

FinallyOffRoad

I actually didn't get the gauge. I just assumed it was the pump and got lucky!