121k mile 5spd SE, custom exhaust, (2.25" from Y pipe all the way back, hi flow cat, Flowmaster) replaced fuel and air filters, replaced plugs, etc, power comes and goes, seems to be held back until about 5k, can feel surges when going through the gears, exhaust lessened the sensation, but did not remove it, old cat was trash.. Anyone have this problem? And how the hell do I get rid of it?

Many thanks for helping a newbie.

Jim

 

Try the FAQ. Not sure, but could be the VTC is not working properly. I think that's the variable timing control module.

-V

 

Have you replaced the throttle body sensor? I believe that is supposed to be replaced at about 90,000. My car started idling funny at times and when I would heavy accelerate, it was like the car was being held back until it hit a certain rpm, then it would take off. Now that I have had it replaced(137,000 miles) the car is probably 1/2 second quicker 0-60 and it does not act like it is being held back. This tps sensor controls the idle,timing,gas feed, etc. My car runs now like it did when it was new.

Scott

 

Hmm, I'll have to check my TPS someday. I've got this weird problem once in a while where I'll just be gently accelerating and then I hit this spot in the gas pedal where if I push it down just 1mm, it takes off like a friggin' rocket, but if I let off (to prevent rear-ending the guy infront) just 1mm, then I'm decellerating. Only seems to happen for a few seconds when the engine's changing from "warm-up mode" to "normal temp mode" though, if it happens.

Did you do the voltage-test on the TPS first, or did you just go and replace it?

 

what exactly is the throttle body sensor... electronic component??

 

how do you test the tps ? what readings are you supposed to get from which points?


and how much was the tps unit?$$$

 

I did not even test my sensor. I had 137,000 miles and it had never been replaced. It is only about $60 for the sensor and if you have over 90,000, it probably would be a good idea to replace it if you are loosing power. For those that are unfamiliar with the throttle body sensor(tps) it controls the idle, timing, gas feed, etc. and sends it to the computer. I don't know a lot about it, just that it is an important part of the system that if it is bad, can cause your car to run like crap. Since I replaced mine, my car is much quicker now than it was, just like when I bought it new. Hope this helps.

Scott

 

I will get a new TPS this week and let you know how it works, I never thought of that, ever though I've adjusted and/or replaced about a dozen of them on 5.0 Mustangs..

 

Thanks too!

 

where do u put the throttle body sensor? is it that hard?

 

It should be located near/next to the throttle body. Should be easy to replace. I don't know right now without consulting my service manual.

I suggest getting a service manual of some kind. Haynes makes easy to read manuals that aren't too expensive.

 

I would recommend a service manual such as Haynes or Chilton too. Because when you replace the tps, you will need to check your idle and possibly adjust it. Once the tps is replaced, I think it take a certain amount of times starting the car for the computer to reset it to the new sensor. So, don't be alarmed if it does not run 100% perfect the first time you start the car. Again, I don't know a lot about these things, but I have picked up a lot of knowledge from this bbs and can now do some of these things myself.

 

I got quoted $130 for the throttle body sensor by a Nissan dealer... could anyone give me some more specifics on exactly what this thing is, where its at... or am I just gonna have to get ripped off?

 

dealer here in toronto canada quoted me $88 bucks before tax.

 

Without running the car on a dyno you have no real way of seeing if you lost power. The best thing you can do is a couple of 3rd gear pulls from 4000rpm to the rev limiter and time it with a stop watch.

 

!!!!!!!!!!!!!
i ordered a new one, and paid $36.?? w/tax!
i cant help you much with the installation or what it does, mainly because its just sitting in the box, i havent had a chance to put it in.
now whats this about adjusting the idle? i was looking through the only haynes manual i could find and it seemed to only cover VG engines (85-92). are there any websites that would tell me how to make sure everything is ok after the new TPS is installed?

 

hey what dealer did you get it from... phone number would be helpful

I'll just order from that dealer... unless shipping is $100 I'll be saving money.

thanks

 

i didnt get it from a dealer. rather a local hole-in-the-wall parts shop.
just as an update: i installed the new TPS. man, easiest thing EVER. i have more trouble unlocking my doors with the key.
anyway, just as someone said the idle was higher w/the new TPS (2300 cold, 1800 after the first "drop" and 1500 at norm temp.) so i adjusted the idle by gouging a small piece of metal out from under the "rod" that holds the throttle plate thingy to the throttle body. well, now when it first starts, 1700, 1200, 900, then after about 20 minutes of driving, 750.
what gives? why is my car running to well now? yes, i'm questioning why my car is running GOOD. i'm not complaining, i just want to know that its not going to pull the same isht its been pulling. (sometimes not starting, sometimes when starting, running bad...)