1uz vvti help

[triptek]

I'v got a problem with my 1uz vvti and I'm completely out of ideas. Here's a description on whats happening.

It misfires at idle but only when warm. It's fine on cold start. In park and neutral it misfires all through the rev range. In drive,reverse,2,1, if you just slightly raise the revs to 900-1000rpm and above the misfire goes away and the motor runs great. Also the misfire is coming from cylinder 1. Here's a list of things that i'v tried.

Compression test 175 - 180psi on all 8
Leak down test all good
New spark plugs
Replaced Maf
Replaced o2 sensors
Switched coil pack from another cylinder
Switched injector from another cylinder
Injector is pulsing
Coil is firing
Cleaned throttle body
obd2 scan only codes are for the rear o2 sensors, car ran fine without these for a few weeks before this problem started.
Checked for vacuum leaks
Checked shim clearances

Any input would be greatly appreciated.

[Sciflyer]

Presumably runing on factory ECU, could be the usual dry caps problem? That can cause wierd shit on non-VVTi's...

[George]

Would highly recommend to check sensor readings with obd2 scanner. Among other things that would confirm dead caps.

There's a quick and dirty way for troubleshooting sensors (and their ECU inputs). Just disconnect them one by one thus entering limp mode and see if something changes.

Also, since yours is vvti engine, there's quite common problem that control valves (and rarely cam timing gear) get stuck somehow. Even if you pull valve out and check that it moves ok when you apply 12v to its terminals, there's still a chance it would stuck when put in place. This kinda behavior is usually associated with vvti and cam sensor error codes, but I know some cases when the problem was in the vvti control valve and no vvti-typical errors were read.

[mullett]

Hey man

I couldn't find those 4 wire sensors...

-RM