LS400 surging and dying

[Mthomas]

Out of the blue engine is surging and dying and check engine is either blinking or staying on.  Sometimes will run with no issues.  Scanner will not read codes and jumper between E1 and TE1 will not show codes.  ECU? Any assistance would be great.

[sha4000]

It may be the ECU but could be something else. When the check engine is blinking it usually means that the engine is misfiring and in danger of damaging the cats.

[Lexus_DK]

Did you recently do any type of service to the vehicle prior to the engine idling erratically/surging?

[Mthomas]

No.  Everything was normal until this started to happen. 

[Lexus_DK]

hard to say. Check the throttle body for carbon build up on the plate, clean it. Check the fuel pump dampers. Check for vacuum leak. Check mass airflow sensor.

[Mthomas]

Can't understand why analyzer can't connect or be able to jump terminals to obtain check engine code.  

[Lexus_DK]

Anyway you can take a video or pictures?

[Mthomas]

Pulled ecm. Anyone have luck with a supplier for rebuilt unit. Many out there, not sure who to trust. 

[LSPaul]

Also, check the connectors under the dash, where the wiring harness from the engine compartment goes into the distribution block (fuse panel).  Disconnect, wiggle around and re-install first.  If you have Deoxit on hand, use that on the connector contacts. The lack of a signal at the diagnostic connector makes me think you're not getting proper connections at this junction block (I went through this when I bought my '94 and over several months, dug through everything). 

As for the ECU itself, I don't have a suggestion for a vendor to replace electrolytic capacitors inside the ECU.  There's probably more suggestions out there as to who NOT to use for recapping (I borrowed a 'rebuilt' box from an acquaintance when I had to replace caps in my ECU, and it was worse than the original box!).   If you have any electronic soldering skills, consider re-capping the ECU yourself; *much* cheaper than sending it out.

[Spartan0536]

I am having surging issues myself, my mechanic said it has to be the ECU after testing and cleaning the IACV, throttle body, checking all electronics.

I contacted LScowboyLS on Facebook, I am currently attempting to make sure that he is legitimate, his posts on ClubLexus are extremely detailed.

Interestingly enough in my conversations with him he has self proclaimed to have worked for NASA with his father at the Marshall Space Flight Center in buildings 4227 and 4708 @ redstone arsenal near Huntsville Alabama. If this is true this guy is an extremely rare find, which is why I am trying to verify his credentials. On his facebook page he has tagged himself with the ASE Master Mechanic certification, unknown if this is legitimate.

Any insight into him from anyone?

[M.Yasir]

Check engine light blinking, why jumping directly to the poor ECU, check your spark plugs or ignition coils, i had the same issue my CEL was blinking suddenly and car started jerking at 60 MPH while at idle it will not jerk

I replaced all the 8 spark plugs and kept the same ignition coil... butter smooth it is

[Alexander the o.k is back]

These seemingly unrelated problems sound like the old chronic Ls400 trunk hinge issue: http://us.lexusownersclub.com/forums/index...showtopic=50087

"This same type of problem happened to me about a year ago. This smooth world class car started balking, cutting out, lurching, wild rpms, dash flickering, radio went out when hitting the brakes, just seemed ready for the junk yard. It happened all of a sudden. No warning. Now it's smooth as silk w/ 255,000 miles on it. Open the trunk. On the left side you will see a wire harness on the left hinge. After repeated openings and closings the wires inside that harness become fatigued and frayed. Then they start shorting out. Then sputtering, and stalling. This is a design flaw and lexus knows it. If this describes your problem, then remove the plastic bracket on the left hinge, strip down the harness, untwist all the wires, re-connect, then re-tape.. Don't assume they are good- strip them down and examine them. Make sure to leave off the hinge bracket that ensures tension on the harness. Just let the whole mess swing free and loose. In my case, problem solved, and no spending thousands of dollars in diagnostics, parts, and tech snafus. Best of all, it's free. Takes about 30 minutes." Post back what you see at the hinge.

Alex

[Exhaustgases]

Or idle control motor bearings seizing up.

[vissine]

Before messing with the ECM, you should check the ignition coils.