Confused...Bad TPS?

Hey guys! When I start my truck in the morning the rpm's start at about 1600-1800 and then immediately drop to 500ish and then jump back up to 1600-1800ish until it warms up. Then after I back out of my driveway and put it in D I push the gas and it hesitates for a second and then drives like normal. Ive changed the plugs to OEM plugs and changed the wires to NGKs and cleaned the K&N and its still the same problem. Ive read a few threads about APPS and TPS but it just confuses me Also would this effect my gas milage? Ive been averaging about 250-260 a tank and when I bought the truck I was around 300-310. Thanks guys!-Swanny.

 

Try cleaning the MAF if you have a k&n filter. Can you try to adjust the tps sensor?

 

I did clean it. It was black on the leading edge so I cleaned it with a q-tip and brake parts cleaner and still nothing. I've read about adjusting the TPS but doesn't it work in conjunction with the APPS? And if its miss adjusted it would make it worse?

 

Swanny,

Seams like this thread might be useful... around page 4, looks like most of these folks replaced the TPS sensor. Seems like some initial confusion with getting the right part, but people seem to have success with the 4 prong sensor . Maybe pm Markmmg and see if he's got more. It could be so many other things though.

http://www.tacomaworld.com/forum/toyota-trucks-suvs/227204-2003-toyota-tacoma-v6-hesitation.html

 

man, you don't use brake parts cleaner on it. there is a good write up about cleaning it, use only MAF cleaner, and don't touch the wires inside. overoiling a K/ N filter even just a little bit over time will coat the wires with oil and lead to failure. I had one on a mustang gt for many years, never ruined one but did over oil several times.

and if not this, have you cleaned the Idle air valve?

 

Whoops.... Ill get some MAF cleaner and try that out... Ill also try cleaning the IAC. Hopefully thats it.. I read somehwere that TPS's are coded and have to be done at the dealership so the ECU can read it? I might be wrong.. Thanks for the help guys Ill update you after I clean everything..-Swanny..

 

Hey Frank, Ive been Sub'd to th at thread and Ive been trying to keep up with the posts.. Thanks bud!

 

without knowing how many miles on your truck, I would doubt that its a TPS, but its prob. the IAV, they can be a pain in the ass. when I got mine it has 176,000 miles, so I have gone through and done all the high miles maintenance jobs. I cannot stress enough about the MAF sensor, they are easy to maintain, and they are easy to mess up, and they are $$$ to replace. they changed the design on those i think from mine to yours, could be wrong, but I took mine out and used a flashlight to spot the wires and spray. but the 2 wires on the MAF sensors are sensitive to the oil on the KN filter and don't touch them with your fingers.
I replaced my TPS with a lot of other things, but she now has 186,000 miles.

 

I have about 130XXX miles on the truck. I cleaned the MAF today with MAF cleaner and followed the directions to the T. So Ill see how that goes. My gas mileage has been pretty shitty so hopefully this helps.

 

one thing to do after that is to reset the trucks computer. if its never been done or you don't know if its been done, its prob. the IAV. wonderful little thing for emission that gets clogged up and screw with mpg. with 130,000 you might just want to take some time and do the throttle body cleaning with that, since its on the side of the throttle body, when I did mine it was black tar, and goo.

 

I installed an optima yellow top last week so the ECU was reset. If I remove the tb can I remove all of the components and be ok? Bc I know that the TPS is adjusted to the APPS. I want to make sure that when I install everything back on the tb its going to work correctly.

 

here is a write up with pics. http://mississippi-mud.com/Thread-DIY-cleaning-Throttle-Body-and-IAC-on-Toyota-3-4

I never messed with my TPS then, I did go ahead and replace it last summer, I just figured with age, it would not hurt.

but before diving into this make sure you get 2 new gaskets, while you might be able to use the TB gasket again, its not expensive, the little rubber one on the IAV is more critical, its cheap, it rips easy and any small air leak here will cause problems.
again after doing this resent the computer.