Code 71, hesitation, and what to do

Hello everyone. You have all be hugely helpful in solving my mechanical challenges, so I thought I’d test the waters again. When I got my van about a year ago the idle was ridiculously high, so one of the first things I did was adjust the idle screw. I turned it to the lowest setting—which felt a bit strange—but it has purred like a kitten ever since. I really only have two small problems at the moment, and they both seem to occur when I’m on the freeway. The first is that I often get a CEL code 71, a California specific reading that points to the EGR valve (gas temperature). I plan on taking out the throttle body and EGR valve, cleaning them both, and possibly replacing the TPS while I’m there. Seems like a good place to start, although I am a bit intimidated about the whole project. The second problem is that occasionally the Van hesitates when driving 60+ mph…just a little sensation where I press the gas pedal and the acceleration disappears. First time it happened was on a windy day and it almost felt like the wind was holding it back, but it wasn’t. I’m not sure if my catalytic converter is still doing its job, so I purchased an aftermarket bolt on just in case. I do get some strong smelling white smoke mostly at startup, and I think the Van does burn some oil (valve seals?). I thought the EGR would help address the upstream issue, a fresh catalytic converter would help downstream, and I’m adding some Bar’s Leaks Valve Seal stuff for the hell of it. My main question is does this sound like an okay approach and what else should I be looking for? Finally, there’s an intermittent “leaky air” sound that seems to be coming from the passenger’s side of the engine. It doesn’t in any way effect performance, but I’m curious to know if anyone might know what this is. Thanks.

An overtemp signal from the EGR sensor is an indication of a failing catalytic converter, so it sounds like a reasonable assumption. Not sure about the idle adjustment, but that could be a stuck air valve (under the top half of the intake manifold). The air valve's job is to make the van idle-up when it's cold. Unfortunately that valve is expensive and it's a PITA to replace (top half of intake needs to be removed). Not sure about the "air leak" sound, but these type sounds are usually belt related. Put some silicone spray or belt dressing on your belts to see if the noise changes. If it does, then it's a belt noise. If it doesn't, then I'd get or rent a directional headset tool to track it down. Not sure about the hesitation, but check your intake air tube for cracks (the most common cause of hesitation). Tim

Great, thanks very much Tim. I'm going to replace the cat and then move on to cleaning the EGR valve.

Forgot to ask one more question. I bought an Eastern bolt-on catalytic converter, but one that is Federal/EPA approved. My van is a California car, thus the code 71. I live in Michigan and figured this cat would be okay. Do you see that posing any problems?

Only if you want to register the van in CA.

As a quick follow up I wanted to share a story the speaks to the quality of OEM Toyota parts. Long story short, I purchased an aftermarket cat to replace my original. Once I had the original off I confirmed that it was in amazingly good shape (130K miles). It was also apparent that the build quality of the original Toyota cat was worlds better than the replacement: port size was twice as large, the part itself was much heavier, and there's a much more efficient gasket arrangement (inset metal oval gaskets compared to cheap paper flange gaskets). Anyway, goes to show you that OEM parts are most often the best way to go.