Grim Reaper
Expedition Leader
Trying to find some of the relevant links but let me put it this way there is a line in the owners manual on my Suburban that if I run 10W40 they will void the warranty. :yikes: GM feels that strong about the oil.
What the deal is there is really two main base viscosities for engine oils. As I recall it is 10 or 20 and 50. To make a multi viscosity oil they add thinner agents to the 50 to make a 20w50 and for the thinner oils they add a thickening agent (mostly Paraffin wax) to make the 10w40. To get that 40 they have to add a LOT of paraffin. When the oil gets burned by blow by at the rings if makes a hard residue and it starts to collect in the ring grooves and jams the rings making the blow by worse.
The 5w30 you are running is probably helping clean it out. Might want to run a flush next oil change and go to a 10w30 or a 20w50 or even a synthetic. Synthetic 10W40 is usually ok because they can formulate the viscosity without using the paraffin.
On the throttle surge you might have some deposits around the butter fly that needs to be cleaned out. The brake peddle also sends a signal to the ECM. When the ECM see's the brakes and the throttle IDL both closed it goes into a fuel cut mode to prevent deceleration back fires. If the RPM's are over 900-950 it puts the ECM into a conflict and causes the idle surge.
Toyota's PVC design sort of sucks and with the oil you were running and burning all the oil vapors get run through the intake and make a residue that gums up the throttle and sometimes doesn't let the throttle fully close. In fact I need to clean mine out this weekend for this exact problem from the 5w30 the local dealer put in mine despite me asking for 10w30. You might have the TPS adjusted down enough that even though the throttle is slightly propped open it may still be closed enough to trip the IDL circuit and put it into conflict. Also a worn out throttle shaft amy also cause it to hang.
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml is how to check and adjust the TPS.
What the deal is there is really two main base viscosities for engine oils. As I recall it is 10 or 20 and 50. To make a multi viscosity oil they add thinner agents to the 50 to make a 20w50 and for the thinner oils they add a thickening agent (mostly Paraffin wax) to make the 10w40. To get that 40 they have to add a LOT of paraffin. When the oil gets burned by blow by at the rings if makes a hard residue and it starts to collect in the ring grooves and jams the rings making the blow by worse.
The 5w30 you are running is probably helping clean it out. Might want to run a flush next oil change and go to a 10w30 or a 20w50 or even a synthetic. Synthetic 10W40 is usually ok because they can formulate the viscosity without using the paraffin.
On the throttle surge you might have some deposits around the butter fly that needs to be cleaned out. The brake peddle also sends a signal to the ECM. When the ECM see's the brakes and the throttle IDL both closed it goes into a fuel cut mode to prevent deceleration back fires. If the RPM's are over 900-950 it puts the ECM into a conflict and causes the idle surge.
Toyota's PVC design sort of sucks and with the oil you were running and burning all the oil vapors get run through the intake and make a residue that gums up the throttle and sometimes doesn't let the throttle fully close. In fact I need to clean mine out this weekend for this exact problem from the 5w30 the local dealer put in mine despite me asking for 10w30. You might have the TPS adjusted down enough that even though the throttle is slightly propped open it may still be closed enough to trip the IDL circuit and put it into conflict. Also a worn out throttle shaft amy also cause it to hang.
http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml is how to check and adjust the TPS.
