EGR Valve
 

I've been meaning to post the cure to my Toyota's hesitation problem.

After having the EFI cleaned twice, the power steering fluid flushed, the transmission fluid flushed, and the other items listed in this forum checked, I decided to just put up with the problem - car was running great outside of the hesitation.

A few months later, it eventually turned out to be the "EGR" system. Sometimes the problem isn't bad enough to turn on the applicable check engine code (P0402). The computer system finally registered and identified the hesitation problem. Once the dealership replaced the EGR valve, all was good again. Hasn't hesitated since then.

My toyota and I are back in Germany and it is very happy to be able to run at 90MPH to and from work (autobahn). It doesn't care much for inner-city travel, although we have to do that, too (of course).

Sadly, the transmission is starting to show signs of aging. About a 2 years ago I noticed a high pitched noise when giving low steady gas to maintain lower speeds (40 MPH) or when coasting at lower speeds. Guess this is to be expected for an engine with 175K miles on it now!

Thanks for posting back with the fix.

If a trans problem say a bearing the whine typically gets worse.

If possible shift trans to Neutral when coasting and determine if the noise is still there.

Assume the trans fluid level is OK but might check.

Just wanted to pitch in with my experience - similar 2001 V6 with now 190k. Hesitating on light throttle in the 1700,1800,1900 rpm range at 60-70klms. I was convinced it was the throttle position sensor (which incidentally was showing odd resistance and something of a flat spot). Anyhow a way to test if it is an egr is easy. There is a vacuum tube (black rubber tube) going to the top of the egr valve. Remove this and block it so it is air tight, this will stop the egr activating - and causing the problem. I used the bottom of one of those little birthday candle tips, the spike put in the tube and electrical tape. You may want to also block the entry into the egr - stop anything getting in there. Now drive! Debateable if this a permanent fix, but at least you can relatively easily test the problem. I had cleaned and tested my EGR and all seemed ok except that it made no difference. On doing the above the result was clear ;).

Thanks for the input about how fixed your problem. How long have you driven it like this and have you noticed any issues?

At a guess I think it has been about 4 months, the engine does have a slightly different sound to it at times other than this no problems. As far a fuel economy goes on a recent country trip I had figures approaching 8l/100k!, around town things are pretty crummy, however Sydney is very start stop etc. I have read various opinions on egr and fuel economy, will have to assess as time goes on. I have probably done around 4000ks since blocking the vacuum tube, as soon as I reconnect the problem returns, a new egr here exceeds $300 AUD and that is just for the part...

A further update on the EGR, I have been tracking my fuel consumption fairly rigorously and it would seem the country driving figure is good - without the egr the round town is terrible. I am a bit of a feather foot and it would seem with the egr reconnected and not working as well as it should I am getting just over 10l per hundred k's in the city, with it disconnected this figure is at 13 - 14l. So while this is anecdotal evidence, it does show some example of how the egr isn't just for nox, at least in the case of the camry!