toyotas pretty good

Hi, I've owned a few Toyota's and am pretty good at fixing things but my girlfriends 98 4runner, with the 3.4 5vzfe 5speed, has a very odd issue. When driving on the freeway for extended times, above 60 mph, after slowing down and trying to accelerate again it boggs down and billows blue smoke out of the exhaust. It happens in puffs and doesn't happen very often. It looses a lot of oil when this happens and also coolant.
It seems like a head gasket but it doesn't have any coolant in the oil and also no oil in the coolant. It drives completely normal up to that happening and returns to normal after all the oil clears the exhaust. It is hard to accelerate when it happens but after a bit it is fine. The only code is for a throttle position sensor and I have replaced the pcv valve.
I can't find anyone else with this problem and don't want to take it to a mechanic because of money. If anyone has any ideas it would be appreciated. I was going to replace the head gasket but I don't think it's the problem and would rather not bother if it isn't. Thanks,

dropzone

iTrader: (6)

always thought blue smoke indicated burning oil as in bad rings and white smoke- aka steam indicated head gaskets..

so the code is for TPS, have you diagnosed/replaced it?

toyotas pretty good

Yeah it is burning oil but it doesn't smoke at any other time, even when starting. Just randomly on when on the freeway for a long time, and when it happens it burns enough to make it drop off the dipstick. The tps has been bad for a long time but I don't know how it could effect it smoking?

wyoming9

iTrader: (1)

Time for a compression test!! a coolant system pressure test would be a good idea as well !!

It burns enough oil that the level is off the dip stick in one trip ??

Since you don`t mention mileage is it up like 250,000 miles plus

Cracked Head or heads only causing problems after extended heat build up

What does it look like behind the throttle body is this mix being drawn in to the intake or directly into the Combustion chamber

toyotas pretty good

Hmm, I can check behind the throttle body later. Would a compression test reveal a cracked head, and has any one else had a cracked head that only acted up when it got hot? it does have around 250k so I don't doubt the head being bad just would like to rule out other options. Thanks for the reply btw

75w90mantraN

Compression test can tell you all sorts of things, including cracked heads. Since you're also burning oil, a comp test can tell you about your cylinders and rings. Worn piston rings is one way to burn oil. At 250k, it's time for a lot of checking, as Wyoming pointed out.

Cheap way to do a compression by renting/ buying a gauge tool that hooks up to the sparkplug hole. Wealth of knowledge online on how to use. Let us know what you get.

See if you can search up as far as fixing the tps. Unless that got taken care of already.
I'd bring an extra qt of oil for top offs just in case, too. Hate to hear about driving around with low oil levels.

If it is worn rings, prepare for some needed work, or a trip to the shop. In the meantime, maybe a thicker oil, but not crazy thick. Others can rain their fire or offer their input. Good luck!

75w90mantraN

search on "burning oil piston rings"
https://mechanics.stackexchange.com/...ne-to-burn-oil

toyotas pretty good

Okay it has been a while, I appreciate the help. Following up on wyoming9, i looked into the intake and there is a shallow pool of sticky black oil (I'm certain that it is oil it has no gas smell) right under the throttle plate, could that reveal anything? Anyways i looked through that forum and I'm leaning towards valve seals. That being said it still would require a new head gasket and to pull the heads off, so it would be a while. I bought a compression tester $20 at harbor freight because i figured I would use it on my other cars too. What do you guys think about pulling heads from a local u-pull, they are around 40 bucks each complete which i think is a steal especially considering i have bought eBay heads for a lot more that have failed in the past?

RDubyota

Can't say about the pooled up oil. Not something I have ever encountered.

I suggest you save up a bit of $ and try to use the heads you have....here is why, you are taking a big chance that the "u-pull it" heads are actually good to go. You may get your new to you heads installed only to find the same or a worse problem. Now you have 2 sets of heads that are useless until they are repaired. Not to mention the added wrench time of having to do the job twice.

Every time I pull heads I take them to a machine shop to have them "true them up". It is an added step but it takes all of the guess work out of the heads. They can check for cracks and even repair them, within reason of course. While they are there they can install new valve seats and guides/seals if needed. But I suggest you order the parts yourself before hand, having the machine shop do it will take more time and they may charge fees. It can be more expensive depending on the machine shop and whether or not there are competing shops. The last time I did it was on a '82 22r. They found 3 or 4 cracks, head was warped slightly, and they repaired a few of my exhaust bolt holes that I hadn't noticed were semi stripped out because some douche canoe put bolts in that had the wrong threads. All repaired for around $150...can't remember the actual price. Of course the parts were more but I had purchased them a few weeks in advance to lighten the immediate load on my finances.

Anyway, just my 2 cents. Hope it helps.

toyotas pretty good

Thanks for responding, I have decided to take it apart this weekend as i found a head gasket. I'm gonna take the heads to the shop to get them surfaced and the guy leak checks them when he does it. 130 for both I think that's fairly reasonable. Well I'll see how it goes, gonna follow a video on YouTube to do the job. thanks for all the help I really appreciate it

toyotas pretty good

Heads are getting resurfaced right now. This engine had a ton of sludge in it. So much that some of the oil galleries to return oil from the head were just plugged with the stuff. I wonder if that could have caused oil to pool up way to high in the head and come out the pcv or something. Anyways hopefully it fixes it although no signs of cracks or bad HG yet.