Metalhead1

As you know I have a 90 4runner with the 3.0. Heres the problem, it will sputter and buck at approximately 1500-1800 rpm and only there, above 2000 and below 1500 it runs smoothly. It sucks because thats right at crusing speed at 50. Any help will be appreciated!

offroadnutz

Prob a TPS but check for codes.
http://www.troublecodes.net/toyota/t...up-or-4runner/

Metalhead1

The Tps is in specs so I changed out ecu's and each one threw a different code? one threw a 53, one a 52, and one a 12. I do have a service manual but why would each one throw a different code. The one throwing the 12 wouldn't let the vehicle move forward when placed in D but would move in R and it only did it with that one. Are ECU's different for automatics and standards? they are out of standards and I have and automatic. Thanks for any help.

Shady Cadence

The ECU controls the engine AND transmission on automatic trans vehicles. With a manual, there's no need for this, so different part.

You said the TPS is in spec, did you do an analog sweep of the TPS? It could have just one bad spot right at cruising throttle.

offroadnutz

x2^ The TPS usually goes bad at the spot your throttle frequents the most.When you do the test you want to look for a gradual increase on the meter as you are turning the lever. If it suddenly drops out then you know you have found a bad spot.

Metalhead1

It is a new Tps But we all know new ones can be bad. How do you do an analog sweep? and what pins do you hook up to? Thanks!

offroadnutz

Look here http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

I personally have never seen a new one defective but I have seen many not adjusted properly.

Metalhead1

Alright I reset the Tps and did the analog sweep and it is all good. So I start it up and it starts on a dime, I shut it off and restart and it idles right but can't throttle up like before. So I am thinking it is my ECU I'll swap it out with a friends to see if it is the problem. Thanks for the help!

offroadnutz

Does it do it between 1500-1800 rpm in all gears? What about in neutral/park?

Metalhead1

Yes, in neutral and park and driving. So I swapped out ECUs with my friend and mine ran fine in his and his ran crappy in mine so I know it is not the Ecu. I did a continuity test on the distributor wires to the ECU and all of them tested out fine but two had continuity between them. The schematic shows the wires going direct to the Ecu and at no point do they intersect before it so is this the problem?

offroadnutz

When you did the continuity test did you have the distributor harness unplugged and the ecu unplugged? The wires need to be isolated or you could be getting a false reading.
Have you checked all the basic stuff like plugs, cap, rotor, wires, intake hose? You might also disable the egr or even remove it and clean it and see if there is a change.

Metalhead1

Yes both ends unplugged. It has new plugs, cap and rotor. The wires appear new and the intake tube has no cracks. I was getting shocked from the top of the air cleaner housing but I fixed that by grounding it. When it runs right it doesn't shock me but when it runs ˟˟˟˟ty it does. When it runs right it runs right but I can shut it off and restart and it will run like crap! The Egr does work when I rev it past 2000 rpm I can feel it open and let in the hot exhaust.