P1135...best way to fix??

[QxMan01]

And yes, I have searched prior to posting. Just wondering the most economical way to alleviate this code without taking it to the dealer. Are there aftermarket parts I can purchase and install? I have cleared to code several times only to have it pop back up a few days after. Also, what impact does the intake valve timing control sensor have on vehicle operation? I've had the code for a few months now. I appreciate any input/suggestions, thanks!

[Chuck Tribolet]

1. Did you find NisTech's post on how to tell whether it's the sensor or thesolenoid? That's important. The sensors are easy to replace, the solenoidsharder but doable. 2. If you have a code reader, pull the freeze frame, clear the code, wait for itto happen again, repeat. In my case, it was happening at WOT, 1500-2500RPM. Dr, it hurts when I do X. Dr: don''t do that. By avoid WOT throttlein that RPM range, I can keep it away. 3. In my case, I think it's because the truck has 172,000 miles, and the oil pressure is starting to drop a bit (the cams are moved by oil pressure). I switched from 5W30 Castrol GTX to 10W40 Castrol GTX and that has helpeda lot.

4. It doesn't seem to affect driveability at all. I've been living with it for three years and about 60K miles.

5. I'd love to know why, but it seems to be the '01 PFs/QX4 that mostly havethis problem. It seems to be much less common in the later PF/QX4, andmuch less prevalent in other '01 models with the same basic engine.

[QxMan01]

1. Did you find NisTech's post on how to tell whether it's the sensor or thesolenoid? That's important. The sensors are easy to replace, the solenoidsharder but doable. 2. If you have a code reader, pull the freeze frame, clear the code, wait for itto happen again, repeat. In my case, it was happening at WOT, 1500-2500RPM. Dr, it hurts when I do X. Dr: don''t do that. By avoid WOT throttlein that RPM range, I can keep it away. 3. In my case, I think it's because the truck has 172,000 miles, and the oil pressure is starting to drop a bit (the cams are moved by oil pressure). I switched from 5W30 Castrol GTX to 10W40 Castrol GTX and that has helpeda lot.

4. It doesn't seem to affect driveability at all. I've been living with it for three years and about 60K miles.

5. I'd love to know why, but it seems to be the '01 PFs/QX4 that mostly havethis problem. It seems to be much less common in the later PF/QX4, andmuch less prevalent in other '01 models with the same basic engine.

Thanks for the response...I did read nistech's write up on this issue, and have found that it's probably the solenoid and not the sensor; the light pops up while I'm driving, not after vehicle start up. I also suspect the drop in oil pressure is a contributing factor. I took it to the dealer on black Friday and they mentioned that issue, and just topped off the oil and cleared the code. Is there anything specific relating to the oil pressure I can do to avoid the issue? I have around 152k on the truck...is there any specific grade of oil that is better than others for high mileage vehicles? Also, could it be there is not enough oil circulating? I have read that the pathy's/q's need anywhere betwen 5-5.5 quarts of oil. Should I bring this up at my next oil change (within the next few weeks I will probably have the oil changed)? Thanks in advance!