silvertaco4X4

hey everyone. i posted a while back about the "cold start knock" i was hearing on my 2000 taco. at that time i was at least happy that nothing else was wrong with my truck. since then, the idle on my truck has been getting worse and worse and the exhaust seems way louder than it ever used to be. ive also been hearing ticking noises that i havent been able to locate yet.

i had the truck in last week to a dealer that is about 40 minutes farther away from me (already took it to local dealer), so they could listen to the piston slap noise that it makes and also check out the idle. the tech that i spoke to actually told me "sometimes these engines just sound like they are going to fall apart" but according to him - everything is just fine. not that mine sounds that bad yet, but maybe in time. he said the idle was fine also. it feels to me like it keeps missing but the needle does stay right at 750 rpm. the truck just feels so weak sitting at stop lights i swear if it gets much worse id say its gonna start stalling out on me.

now, ive tried some easy things in an attempt to help with the piston slap, im beginning to wonder if ive just been causing other problems. i did take of the egr valve a while back to look at it, having to unhook and reconnect vacuum hoses, ive cleaned the throttle body, changed the spark plugs (plugs were after idle starting going to *&%$ though and didnt make a difference that i could tell), ran some techron through it and changed the oil and filter about a million times. probably some other small things that im not thinking of right now. i dont THINK that i messed anything up, ive looked back over the vacuum hoses multiple times now and cant find any problems (i even labeled them when i took them off). the best i can think is that maybe i should have put new gaskets on the egr valve. ive gone over the engine with a tube and tried to listen for any leaks and dont hear any, and that includes the exhaust manifold. another thing - a friend and i did change the belts not too long ago, but that seemed to go great. is it possible to throw off the timing or anything doing the belts? if we unintentionally turned a pulley a little or something trying to get the belts off?? this is a 2000 taco with the 2.7, 4X4 and i have just over 100k now.

many apologies for the long post. im just at a loss here. anything that anyone can throw at me would great. the dealerships are offering me nothing.

thanks.

wrenchmonster

Re-check the EGR. Is it stuck open? Did you clean the passageway or just replace the valve? Perhaps a piece of carbon is hanging up.

Also, how is your power? Gutless? I'd do a back pressure test on the exhaust to check for a clogged cat.

No mis-fires? None at all?

You wouldn't have done any harm by changing the accessory belts.

-Wrench

silvertaco4X4

The EGR valve seemed to function fine. It was not stuck open and it did move freely. I'm not an expert so that's all I checked for. However, there did seem to be like a thick black lining on the inside which probably was carbon-build up. It was so even and hard though that I didn't want to do any damage if that's just what the inside of the valve looks like. I've never taken off an EGR valve before, so I ended up basically just spraying some TB cleaner into it, wiping out the inside (it wouldve taken way more than that to get all the black out) and putting it back on. I have to special order the gaskets so I'm thinking I will go ahead and do that and then take it back off and look closer at it. It'd be awesome if I knew what the diameter of that opening is supposed to be when clean. Or heck, even if someone can tell me there should be NO black in there, Ill scrape the freakin guts outta that thing.

As for power, well.. I suppose Ive kinda been babying the truck since all this is going on, but yes, I would say at least a little power loss. Definitely most worrysome at idle though. I should probably take it somewhere to have the exhaust tested right? And does a clogged cat mean a new cat or just unclog it?

It certainly feels like its misfiring (for all I know - is that the same as just missing?) although I've seen no CEL through any of this. I've been meaning to make a trip to Autozone to see if they can pull any codes for me. No light doesnt necessarily mean no codes right?

Obviously my knowledge is limited, so sorry for so many questions. Really appreciate the reply though. Thanks a bunch.

wrenchmonster

The EGR valve should be free and not get stuck open or closed. If you question that this IS your problem, you can plate it off temporarily and see if your idle evens out and other problems go away. Keep in mind that plating off the EGR will set your CEL. Be careful with cleaning for now. There are professional chemical kits that do this, and you can do it yourself, but I wouldn't put the cart before the horse.

As for the catalytic converter.... how many miles do you have? If under 80K you should be covered by your warranty. Backpressure test is done pre-cat through the o2s hole with a gauge. You pretty much have to have the tool, short of just taking the cat off and inspecting it. You can also do temperature performance tests to see if the cat is working properly.

Definately get your codes pulled. This is the very first thing I would do. This may clue you into what is going on. And yes, no light doesn't equate to no codes, however most dealer training dictates not to diagnose soft or history codes as they may be considered "intermittent" and can lead to unnecessary repairs. Hence, your dealer may not have told you of these types of codes being set.

Where in NOVa are you? I grew up in Annandale. Just curious.

-Wrench

silvertaco4X4

I wasnt thinking that the EGR valve itself was my problem, although who knows. I was mostly worried that I created a vacuum leak or something in the process of taking it off. Ive read as much as I can and been pretty careful with the things Ive done to this truck but of course, theres a lot I still dont know.

I have a little over 100k on the clock and I'm a second owner so no warranty for me, unfortunately. I will try my best to go have the codes pulled tomorrow night and hopefully at that point there will be something to lead me in a better direction. When I had the truck in to the dealer a few months back, they did say that it had no codes on it (that was only for the piston slap), but I dont think this other dealer checked when I had it in last week (piston slap and idle issue). They didnt mention hooking it up, just said everything was fine. Im not a Toyota technician, but no way, something has to be wrong.

Im in Woodbridge, not very far at all. And thanks again for the help.

silvertaco4X4

Well, I took the truck to Autozone a little earlier to have the codes read.

No codes.

I dont know if that makes me feel better or worse. I guess worse. Looks like Ill be going over the truck with a fine toothed comb again this weekend.

silvertaco4X4

im wondering - seeing as the needle on my tach never seems to move, could my idle problem actually be loose or broken motor mounts? if i stand and watch the engine with the truck idling, i can actually see it rock itself side to side sometimes. it shouldnt be able to move that noticeably should it?

aowRS

The motor mounts are made of rubber and steel - and as such allow for a certain amount of movement. If the truck has an intermittent miss, it could cause the whole engine to rock from side to side. The truck seems too new to have shot engine mounts.

Andreas