Expert: Sean Halliday - 7/24/2009

Question
QUESTION: Hi, I have a 1990 Toyota pickup V6 3vze. When I start it it idles very rough, then dies after about 10 seconds. I have replaced the: plugs, MAF, and fuel filter. I have cleaned the egr valve and the egr vacuum valve. I have also tested the throttle position sensor. I can't think of what else to do. Any help would be greatly appreciated.
Thanks, Jake

ANSWER: Have you done a compression test?Low compression and worn valves will cause rough idle.Other causes can be bad wires,cap,rotor.I would test the vacuum system also for a leak at the intake manifold or at the vacuum hoses.Check also the idle air control valve on the throttle body.

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QUESTION: I have done a compression test and it tested at 150. All the hoses are good, I tested every single one. Where would I check the vacuum at the manifold at? My manual said the IAC was attached to the bottom of the TB with 4 screws, but I can't find it. Does the 3vze have a IAC? Also I'm getting oil in my air cleaner. PLEASE HELP.

ANSWER: Oil in the cleaner is possible valve stem oil seals or worn rings.There is no certain way to test for a leak at the intake.With the oil in the filter problem this could be a blockage in the pcv valve or breather system also.How many miles are on this engine?Fuel pressure good?

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QUESTION: It is a rebuilt engine with 0 miles. I am planning on checking the pcv valve but they really put that in a bad spot. What is the breather system? I am unable to check the fuel pressure, I have a tester, but am unable to find a good spot to hook it up.

Answer
This is a problem,i cannot advise you further as someone else has worked on this and i do not know what they did or didnt do.A rebuilt engine may be either built incorrectly or installed wrong.You will need to start from scratch and go over every single thing on this car,wiring,hoses,vacuum,fuel and ignition.A factory manual would be a good idea.