Ok, my 1994 4wd toyota with 3vze 175k miles maintained by me since new, has a low rpm intermittent miss. All is ok and smooth above 1800 rpm. I replaced plugs, wires, dis. cap, and rotor about 6 months ago with toy parts. My missing problem started about 3 weeks ago. I did get a new (used) igniter and that did nothing. Compression test results a highest of 182 and the lowest was 172, this would rule out valve issues. I checked for a vacuum leak by spraying ether on and around suspected areas. Found no vacuum leaks. Also replaced fuel filter and ran lucas fuel treatment with 93 octane shell gas through it. I also checked coil and distributor with ohm meter, and they check out. I did have a code 14 but cleared it and it has not returned even though the problem still exhists. I think the code 14 was left over from a bad coil about 2 years ago? Any help?

 

i know you replaced the fuel filter but do you know if your getting sufficient pressure at idle, i would check your fuel pressure regulator, oh i would also clear that code and drive it around for a while and see if it pops on again that might be your problem.

 

I did not check fuel pressure. Where on the fuel line on the 3vze would I connect the pressure gauge. I dont see any place to connect. I cleared the code two weeks ago and it has not returned.

 

the fuel line is on the passenger side of the motor and runs down along the fender.

 

I would try to clean the injectors with something that might actually be effective. That's something with polyether amine, and there are only two products left that still have it. Red Line SI-1 Complete Fuel System Cleaner has the most PEA, CRC's "Guaranteed to Pass Emissions Test Formula" has less but still an effective amount of PEA.
http://www.amazon.com/Red-Line-60103...dp/B000CPI5Z0/
http://www.toyotanation.com/forum/sh...72#post2868772

Lucas Fuel Treatment is nothing but paraffin oil, which is essentially a refined form of mineral oil, in the same family as vaseline and kerosene. Probably good for upper cylinder lube, but will do absolutely nothing for your injectors.
http://www.lucasoil.com/images/media...4AACA7BE09.pdf
http://www.pesticideinfo.org/Detail_...Rec_Id=PC41862

Code 14 indicates no IGF ignition confirmation signal received by ecu from the igniter. So since you have new ignition parts and presumably the igniter ground (mounting bolts) is okay since you changed igniters, I would look at the connectors and clean them up if necessary. You say you checked the coil, but did you check it hot, using hot specs? When coils go they tend to get bad when hot first, and will often still check out okay when cool. Unfortunately, it is possible for a coil to check out on ohms, but still be bad, but it's not real common.

Also check that there is no more than 2-3 ohms between ecu terminal E1 and a good chassis ground, between E01/E02 and the engine block & head, between chassis & neg batt post, and between engine & neg batt post. E1 is in the check connector, making that ground easy to check, and that's the one used in the ignition circuits.

Caig Deoxit is the best stuff for cleaning electrical contacts: http://www.amazon.com/Hosa-Contact-R...dp/B0014F110I/