YFZsandrider

I've got a '93 SR5 pickup with 235k miles on the 3VZE. When I start the motor cold, it idles high and the idle speed drops as the ingine warms up. If I drive the truck to my destination, and shut it off for any length of time, then restart, the motor idles around 500-600 rpm with a rough idle. The idle does not smooth out with an increase of engine speed... and if I drive it, it will usually clear out in a few blocks, and act perfectly normal.

I am wondering if this problem could be associated with my coolant temperature? At first, the coolant temp guage seemed to sit on the low side, it would rarely reach over 1/3 of the way up the guage. But in the last week, the needle has reached almost to the red side of the guage, while the heater will blow cool air, only occasionally turning warm.

I read through a couple threads that seemed to point at a common theme with the 3 VZE having rough running issues that develop around the 230k-ish mile mark... I plan on eventually doing a full tune up(cap, rotor, plugs, wires, fuel filter, etc...), but I'd like to get to the bottom of the temp issue soon.

I've had a few 22re trucks, but this is my first 3 VZE...

Could the cool heater air be a result of a bad temp sensor, or thermostat?

Could the poor idle be caused by either of these?

thanks!

YFZsandrider

how would that affect it running rough, then smoothing out?

Also, if I'm going to change the thermostat and coolant temp sensor... should I just stay with a factory temperature, or is it better to run a little warmer or cooler?

YFZsandrider

Update...

So, I replaced the thermostat as a cheap first attempt at remedying the problem... and it now runs at a normal temp, and the heater function is normal.

I didn't anticipate that it was a failing thermostat, as the coolant temp would stay low for a while on start up, then het hot very quickly, but the heater would always blow cold... I thought the thermostat would either be stuck closed, or open.... why did it cause the heater to blow cold, while the engine was too hot?

Also, the engine still seems to have a jerky idle and pulsating power until it hits about 2700 rpm? Any ideas for that?

YFZsandrider

So, all my coolant temp issues were resolved by replacing the thermostat...

I am still experiencing a choppy idle, all the way up to about 2700 rpm. It seems to be getting worse lately, tho. Rather than being sporatic, it seems to happen whenever I drive now.

I read in another thread where someone had a similar problem, and it cleared up after having a mechanic adjust and re-shim the valves... but no one chimed in to confirm that this was a common issue??

Should I just start with a basic tune up? What items should I do on a 3 VZE with 235k miles, besides the usual plugs, wires, cap, and rotor?

Also, how much noise should I be hearing from the valves? Do they usually sound similar to the 22re motors that I am used to?

Thanks!

YFZsandrider

anyone??

JDS1992

I usually hear a little bit of Valve Tick in my 3.0L but not as bad as the 22RE.

YFZsandrider

Mine is pretty noticeable. More so than the 22re trucks that I have had. Are they adjustable in the same manner as the 22re valves?

alecbrobra

If you have not belched air bubbles from your coolant system, it might prevent the a\c heater core from cycling warm liquid making the air blown inside the vehicle cool. Try belching that air out and topping off any noticable drop in coolant.