IamJDev

Here's what I have:
95 taco
3.4L 4x4
auto trans
202k miles
completely rebuilt engine at around 165k
front diff is new, rest is original
33inch pro comps
leaky number 1 cylinder - check engine light pops on once in a while, slow coolant loss.

Ok, here's the WTF... I have no good idea how to explain the cause of this issue, so I'm hoping someone here knows what's going on. When the truck is cold, it idles a little rough, but clears out relatively quickly. So you take off after a couple seconds and the throttle seems relatively normal (no missing it doesn't feel like) but when you start driving it's barely able to get out of it's own way. It's pretty noticeable. You have to rev the piss out of it to get up to speed with traffic.

The funny thing is after the drivetrain and everything gets warm things start to firm up and the motor seems more responsive, more like normal maybe. Moving out into traffic or starting from a light is more snappy, but maybe still kinda sluggish, hard to say... Weird.

Then say it's totally up to operating temp and things seem to be more normal and you go up an incline on a freeway and the thing is dogging out a little. It backshifts and you're mashing the pedal and after it's been around 4k rpms for a few seconds suddenly you get this rush of power that literally will make your head bob backwards. It's totally noticeable to anyone else in the vehicle. You hit the redline almost instantly from there and then it shifts. It's so strange. It makes me think the trans is doing something funny, like the torque converter is bad or something.

However the torque converter being bad (and I don't know if they even can go bad) doesn't seem to explain to me why you have to mash the gas pedal when its cold to get the thing moving. It doesn't feel like it's missing though... it's just sluggish like crazy and it seems relative to A) temperature, B) rpm (if held up high for a bit).

Does any of this sound familiar to anyone? The trans fluid is nice and red and full. Is there another mechanical explanation for the delay and delivery of power like this?

Anyway, I've been wanting to SC the thing, but I've got to get this issue figured out first. I know there are some trans mods that are mandatory for the SC, so maybe i can kill two birds if the trans is funky. Any help is appreciated. Ask any questions you think are relevant.

Could use some good advice. Thanks!
Jason

BigBallsMcFalls

check engine light pops on, what is the code ?
could be a transmission code.

97ltd4x4

Yes,any codes?

food for thought:

A couple of quick checks w/o any codes.How does your intake boot look? Any cracks from the throttle body to the MAF?(you should remove and flex it to check)...Engine would torque up easily,causing boot tear to widen,causing loos of power,possibly not set a code for lean condition..would get better the hotter it got.

Could be a trans problem,partially clogged screen,or sicking solenoid,so when it gets warmer fluid could flow through trans more easily.Torque converter,i doubt it,usually if it fails no forward or reverse,and with cold fluid it would work better not worse.If torque converter clutch was engaged it would cause stalling,but a partially engaged could cause problem,but it would get smoked pretty quickly if that was the case.

I was thinking about cat converter getting clogged as well,or exhaust restriction,but that usually takes a couple of mins. of run time before the exhaust backs up.Could check with vacuum gauge.If its a partial clog it could cause almost what you are describing.

When you pull codes,make sure to write all the numbers down(present and history),If there are tons of them,make a note of them,erase them,drive vehical and get it to throw codes again so you can determine which ones are more associated with the vehical acting up

ozziesironmanoffroad

it runs rough when its COLD? well DUH, i know i run rough when i first wake up. you gotta let it warm up before 'mashin the pedal'. good way to blow a HG, drivin it hard before its warmed up. a HG, or an oil delivery problem, any number of things can happen to a cold engine. simple fix: let it warm up before driving it. at least let it idle in place until the RPMs drop to normal, then slowly drive it until it warms up, then let her rip. and i read somethin fishy... your #1 cylinder is leaking after 35,000 miles or so on a fresh rebuild? sounds like a hack rebuild job... my motor has 300,000 on it and no cylinders are leaky. id take your truck to whoever rebuilt it and get them to fix it under warranty. (most places give like 35-40,000 mile warranties, my mechanic gives a 80,000 mile warranty, unlimited years). enough rambling though... pull some codes, and for gods sake let her warm up! lol good luck

IamJDev

Cool - I came back to the right place.

Ok the code. I wasn't clear. The code is for the misfiring in number1 cylinder. It only comes on once in a blue moon. When it comes on it stays for a few days maybe, but then it dissapears. I haven't seen it for a few months. I can even get the truck smogged if I time when the light is off. lol

Ok, warm ups. I do warm it up... that's what I meant by letting it clear out before I drive. I do take it easy on it when its cold. The problem is not as simple as not letting it warm up. It's a distinct underpowered problem for a while when it's cold - Like 20 minutes worth where it can barely get moving. THEN there is the issue when it's been up to temperature for a while and the engine kicks in at high rpm feeling like you have a jet afterburner. That's definitely not because its not warmed up cause that's distinct power difference pretty far down the road...

I'll check out that air boot. I had it off recently though and it didn't look or feel funky, but I can certainly do it again. The truck is mostly an indoor truck and doesn't get driven but maybe a couple times a week to the store and stuff. It's mostly for heading out to the desert and wheeling and hauling my quad or motorcycle.

The head gasket... what a story. The truck has been through 3 replacements, 1 factory recall, for a total of 4 gaskets. Since the rebuild the guys have put another gasket in. In fact, that shop won't do Toyota V6's anymore because they feel it's too hard to keep them intact. They suggest new heads and studs. I read on here a while back re-torquing the studs after a replacement alleviates many of the recurring leaks. My leak apparently isn't really bad. There's no oil in the water and vice versa that I can see. The fluids look good. The shop that diagnosed the check engine light used a bore scope and said they could see a small amount of seeping in the 1 cylinder. So my guess is it's not why the engine runs like crap because there are so few other signs of a head gasket problem. The light doesn't come on often...

The sudden power rush makes me want to think it's trans related. I just don't know enough about it to know why. If it's not tqe converter, clutches cause this type of issue? But then again, that doesn't explain why the engine won't rev in the morning while in gear. I'd think the engine would spin up. Maybe there's more than one problem...

ozziesironmanoffroad

wait, you had 4 HGs done on a 3.4??? WITHIN 200,000 miles? what the hell...? thats not normal for a 3.4, thats typical of a 3.0 that isnt taken care of the way it should be. the 3.4 is as reliable as the 22RE. also, with your power loss, you said its not driven much, that may be the problem. drive it every day to work and back for a couple days, see what happens. sounds to me like its not getting enough run time and the injectors are slowly clogging. run a compression check on the cylinders, especially the #1 cylinder. though it is possible you got a lemon....

IamJDev

It sounds like you don't think it's trans related? Doesn't it seem like it's state related rather than it being a static problem like injectors being plugged? In other words, if they were plugged, wouldn't they always be plugged?

Yea could be I got a lemon, but one head has been replaced, the block and heads have been decked, so what part is a faulty part and what is design? From what I understand there aren't enough head studs per surface area and the aluminum gets tired after so long partcularly after being bolted and unbolted from the block. The factory installed gaskets lasted for quite a while. Thanks for helping me think. I'm still leaning toward trans for the bulk of the issue, but thats only because I don't have a better idea.

IamJDev

Oh, one things I forgot to add. The catalytic converter is new. I had the problem before I replaced it... some damn theives stole it a few weeks ago. That's a whole other topic!

IamJDev

Ring a bell with anyone? Come on guys, I thought this was the best place to get some advice!

ozziesironmanoffroad

it very well could be the tranny slipping... take it into a repair shop for a free inspection, they'll tell you everything wrong with it. (and stuff thats not). anything around the tranny you should probably take into consideration.

carlj75

maybe a bad coil pack??