Off Idle RPM Surge

[Blindaviator]

I have had my 2001 for about a month now and it has had the VVT solenoid left bank error since I picked it up. About a week ago I did the power valve locktite preventative maintenance to insure I didn't hose the engine. During that I removed the VVT and dropped it into some B12 in a glass and let it soak for about an hour. Cleaned it up and put it back in. I also replaced all the plugs with NGK Iridium fine wire plugs since some were difficult to reach otherwise.

 

The SES light stayed off for about a day and then came back on with the VVT code again. Prolly will have to replace it since that didn't work.

 

Today I was having to jump start a friend and I noticed that if I reved the engine up to about 2000 and held it the RPM's would suddenly drop after a few seconds to about 1500 and then start surging 1500-1700 or so until I let off the throttle. I reved it pretty good a few times to around 3500 and it sounded fine. But every time I would try to hold a higher RPM it would drop and start surging.

 

I just tested it again. It will even do it as high as 3500 RPM. It seems like if I push the acc pedal down and hold it at whatever RPM it goes to it will seem to hold it. If I slightly let off the acc pedal it will suddenly drop and start surging.

 

I put my code reader on it and watched the live data. The MAF will stay at the same rate of flow even when the RPM's drop and it surges. The same will happen with the TPS sensor voltage. It stays steady at the same rate when the RPM's drop. The only thing I saw really change was the O2 sensor voltages. But I would expect that with the lowered RPM's.

 

There are no codes either stored or pending.= other than the VVT.

 

What should I be looking for to solve the problem??

Suggestions?

Could the VVT be causing this or should I be looking elsewhere?

[Citron]

Can you watch the vvt output live?

[Acrobaat]

Hi , How is the engine behaving under load / acceleration ? Just wondering if it is the same surging , this will indicate if it is possible fuel delivery issue.

[Blindaviator]

Hi , How is the engine behaving under load / acceleration ? Just wondering if it is the same surging , this will indicate if it is possible fuel delivery issue.

It feels ok under acceleration and highway cruise speed. Just seems to be in park and not under load that it does it. Some research suggest it may be the IAC valve that could be the culprit.

 

 

Can you watch the vvt output live?

Unfortunately that isn't one of the options in the scanner.

 

Also the idle speed and spark timing is a little off from what the specs should be.

Idle is supposed to be @ 700 +- 50 and it is about 850

Timing is supposed to be 14 and it runs about 10

Edited March 7, 2017 by Blindaviator

[Acrobaat]

I think that the IAC valve suggestion sound interesting .I my self had experienced likewise scenario with IAC valve when i was changing the stock intake (at the same time removing LPG system of my car) to little more free flowing ducting .I tapped the IAC straight of the airbox ( i was not sure if the air was metered or not thrue the MAF) and the idle was surging badly , until i tapped into the intake ducting.

I also have removed to clean IAC valve from 1mz engine and the valve had build up carbon crust and was preventing it from rotating properly.

If it was me that's what i would have done try to clean it first mayde even with contact cleaner (electric circuit solvent cleaner) straight into the intake manifold or the better way remove and clean the valve.

Unfortunately i have never worked on VQ engine and cannot specify the exact removal procedure.

If you can advance your timing to 14 it is defenetly worth it.

Good luck

 

[NovaPath]

Mine does it too. I've ignored it, has done it with or without the CEL being on for various reasons. Even when all is well, it still happens. I'm assuming it is normal.