High Throttle Power Loss

[Warrick]

Recently my Z-34 has been experiencing some huger power losses. if I apply the gas VERY slowly it will accelerate, however it doesn't have anything near the pick up it should. I'm also losing a great deal of speed as I climb hills because of this problem. If I press on the gas with any decent amount of pressure at all, it feels and sounds as if something within the engine is just turning over yet nothing is happening. I know this isn't the best way of putting it, but it seems to me like the engine is responding to me pressing on the gas at whatever amount of pressure, yet something just isn't catching in order to pick up at the pace I'm trying to go. I had my car on a computer analyzer a year ago and my mechanic told me that he ran the system over about 7 times, and 3 out of those 7 times, the O2 sensor appeared as needing to be changed. SO i guess at this time I'm just wondering if perhaps anyone knows if this would be what's causing me to loss such a large amount of power, and if so, roughly how much should I be looking to spend on a new O2 sensor? I've also heard that it could be the cad-converter, I'll look tonight after I replace the power steering pump to see if it's hot, I'm planning on cutting it out of the exaust anyway as there are no smog laws where I live. If anyone has any other ideas of what the problem could be, I beg that you post a reply to let me know, as I desperately want my car running at 100% - I'm sure you can all understand how I feel. Thanks again guys, hope someone knows how to help.

[93luminaz34]

My car had very similar symptoms when my timing was wrong, but the power came back like normal after 4G rpm. It turns out my timing belt tensioner had gone bad causing it to lose its timing. As for an O2 sensor I paid around $40 CAN for it.

[SappySE107]

It also sounds like the trans is going but I dunno for sure. Fuel injectors could also be clogged.

When he tested the O2, was the car driven around? Sitting idle long enough will cause the O2 to act sluggish.

[Warrick]

There are only 114,000 kilometers on the car, so I really hope it isn't the trans. And yes the car was driven while the computer was running on it, and was tested while idle as well, just to be sure all errors that may have came up were just that, errors. but keeping the trans in mind, how much would I be looking to spend on repairing that? I know that I keep asking about the prices of things, but that's really the only thing holding me back from getting the work done, because once I know what's wrong with the car, I'm capable of doing the dirty work myself. Anyway, keep the usggestions coming guys, I appreciate them alot.

[SappySE107]

Well, the trans is just an idea but it would most likely be slipping and the fluid would be black if that was the case (not always though). I would really check out the injectors, fuel pump,filter, and fuel pressure regulator. When the pump starts going bad, you won't have much power other than light throttle. The pressure may be fine but the flow just wont be there. The O2 would also cause the car to run super rich or super lean if it was sluggish and not responsive, but again the fuel flow would also cause the injectors to act up and at extremes the O2 will look like its sluggish when really its just not seeing anything close to what it wants and will hang around the same voltage readings. Did the O2 readings hover around .9x or.0x a lot, or near .4-.6? If its .4-.6 is just the O2 not working too well (or not warming up from being at idle). Best to figure out one thing at a time I think.

[pocket-rocket]

Just a little FYI, I paid just over $20 US for my O2 sensor this weekend. Not an AC Delco, but OEM type.

[grandprixgtp_91]

i cant remeber how much i paid for my o2 sensor but it was from gm and it was definatly under $50 canadian. i will always buy gm parts for my car, i figure if they lasted this long they have to be good!

Jake

[Warrick]

So you guys think it's the O2 sensor then? I had the car out for a run today, took it out on the highway, and it seems like it's most noticable at high throttle, very hard to detect it at medium throttle, and practically not there at all with light throttle. I also noticed that I don't so much lose speed going up hills, I mean, there is a little speed loss, but it's more that I have a harder time speeind up while going over hills. I know cars don't generally accelerate as well going uphill, but a 3.4 DOHC shouldn't have any trouble going from 100 to 120 or even 130 while going up a moderately steep hill, say of about 25-40 degree incline. Hopefully this added information will help you guys figure out what exactly is the problem. I've been busting my brains trying to find tell tale signs that it definitely IS my O2 sensor before I cash out for one. It may only be $40 Canadian, but that's $40 I could put towards a pump or gasket seal should either of those turn out to be the problem. Anyways, as always guys, thanks for the help and hopefully someone will know the answer.

[pocket-rocket]

A 40* incline is pretty steep. I think any car would have a hard time going up it. You live in the mountains?

[Warrick]

Nah, I live on the East coast of Canada, the very furthest east you can get. And the city I live in was planned like a goats path so it's full of messed up hills that are rediculously steep. But even just 25* inclines are a little difficult to gain any speed on for me at the moment.

[manny]

In addition to what everyone above said, also check your throttle position sensor. The TPS is a potentiometer, and if any section of it fails, that's where your throttle, will give you problems.

If your timing has jumped, you could get really crappy high throttle reponse. In addition to your tensioner pulley, make sure your belt hasn't started to "walk" and shave itself off against the belt covers. If it has, change your idler pulleys. (go with the dealer for idler pulleys, the part stores wont know what you're talking about, and they'll try to sell you a drivebelt pulley)

[Warrick]

Thanks for the help, I know this may sound stupid, but I have no problem admitting that I'm no expert when I ask this, where would I locate the TPS on my Z-34?

[93LuminaZ34va]

On the throttle body, opposite side from where the cables hook to the throttle blade for your throttle body.

[RednBlack]

Nah, I live on the East coast of Canada, the very furthest east you can get. And the city I live in was planned like a goats path so it's full of messed up hills that are rediculously steep. But even just 25* inclines are a little difficult to gain any speed on for me at the moment.

Even 20 deg slopes are super steep! Black Mountain in N.C., is only 8 deg. And that is a hard pull on any car! Ask Aaron, he lives in the mountains. (or real close) If you want acceleration on a 40 deg slope, you need more than a V6. (Rockets come to mind) I agree with Ben. Check fuel pressure.

[Warrick]

But the thing is I've never had problems getting power on hills. Thanks for the heads up none the less. I'm going out this weekend coming and buying some parts to try out. I'll start with the cheapest stuff and keep testing, that way when I find what the problem is, I can just return the more expensive and unused parts. In the mean time, keep the help pouring in guys, I really appreciate it all.