Smarly

1999 SR5 V6 125000 miles and all of a sudden the acceleration is horrible btw I have to damn near floor it to get 50 mph I have replaced the fuel filter(OEM), Air filter(OEM), plugs(Denso), and now the plug wires(NGK). Has this ever happened to anyone else? I dont have the money to take it in but i do have a OBD II reader i bought off amazon(MS300 Autel OBD-II Code Scanner). It has thrown Codes of PO300, PO303, PO304, and PO306. before and after plug and wire instals. I dont know what to do now?

Cuthroat72

Do you have any performance mods done to your engine? Any recent changes in the engine temp or other recent engine codes? Have you changed the timing belt in the not too distant past? The more information you supply, the quicker you will get a diagnosis. However, that is a pretty low mileage engine to have this kind of problem.

Good luck!

skoti89

someone on here can probably tell you what those codes are, I definitely don't know. I think maybe a factory service manual can tell you, or maybe a google search. good liuck

Cuthroat72

The codes are for a misfire in those cylinder numbers, if I am not mistaken...

87-runner

Don't remember to well but i believe those are all misfire codes.. po300 i think is multiple/random misfire and the others for cylinder 3,4 and 6. Make sure the wires are pluged in all the way.

Smarly

@cuthroat72 No modes excet for deckplate mod which was done several years ago. I know what the codes are P0300 is multiple misfires PO303 is cylinder 3 PO304 is cylinder 4 and so on. 1st thing I did was clean the MAF as its such an easy job, Air filter, then the fuel filter, the plugs, then wires
current gas mileage is 9.5-10.3,mpg used to get 17-18mpg. Its pretty much stock except for the deckplate mod

Smarly

At this point Im at a loss the only thing i didnt do was gap the plugs as the guy told me they where gapped to factory spec and i shouldnt touch them

Cuthroat72

How does your oil look? Anything funny with the temp gauge? It's a little confusing because cylinder three is on the Right bank (passenger side) and 4 and 6 are on the Left bank (driver's side).

tunnelmotor99

Does it sound like the engine is bogging down when you gas it? if so, it may be the catalyst in your catalytic converter broke apart. I've seen this happen a lot, it breaks up and blocks the exhaust. Try tapping the converter with a rubber mallet and see if it sounds like a bunch of rocks in there. If you had a bunch of misfires previously and drove the truck while misfiring, this can overheat the cat to where it will break down. Once I worked on a Honda Pilot that had the rear bank upstream converter break apart, which plugged up the downstream converter and burn it up too! That was an expensive fix!

Smarly

@cuthroat oil looks fine good level and changed within the last 2000 miles
@tunnelmotor99 Yes it bogs down when i gas it.Im scared to even get on the freeway The acceleration its either reving high at 3000k-4000K rpm or its driving like woooooomp woooooomp wooooomp

Smarly

I was thinking about replacing the engine coolant sensor as I have read about people having similar accelation problems. But @tunnellmotor99 thats thhe scariest thing you could possibly I was under the impression it was a very expensive repair. I threw a P0420 code years ago and reset it and it never came back on.

Smarly

I ran the codes again today and now there is P1133 code

jessed59

what brand plugs did u get? are they double electrode? did you replace coil packs? maybe its the tps sensor? or oxygen sensors? u probably already have but make sure the plug wires are hooked up in the right order and pressed all the way in till they click

cman1

iTrader: (1)

clogged cat

JACKOFEARTH

I dont know about the codes…maybe you have the plug wires to your dis. cap out of order..? But my 89 was bogging down when i gassed it for months till i dropped the tank, cleaned it out thoroughly (with fresh gas and a scrub brush) and changed the fuel pump and screen. now she purrs. could possibly be airflow problem too. good luck

vital22re

iTrader: (2)

What plugs did you use? Did you cross the 3 wires up at all? remember that its 1 coil pack per 2 plugs. I have heard of coil packs going bad. Looks like you need to take a bunch of pictures for us. pic of the wires and how you have them, pics of the boot on the coil. Pic of the plugs. Do you have a compression tester? It would be worth while to check your compression while you have plugs out.
Fixing the codes will fix your bogging down.

wyoming9

iTrader: (1)

All right lets back up here just when or what happened or what did you do??

That started this big problem!!

Something triggered this .

I know times are tough at times are you in the habit of driving around with the gas gauge between 1/4 and empty . Get a bad few gallons of gas with a lot of water???

What did the old plugs look like you pulled out?? Did you get the correct plugs?? From Toyota?? Did you test your old wires to see if they were bad??

I have had everybody but Toyota till me any plugs will work so I gave up and only buy plugs at my dealer

Smarly

Well i think it kinda started years ago when I threw a p0420 code and never fixed. but i have denso plugs double electrode ngk wires everything is set up correctly from write ups mostly on here. I will have to take a bunch of pictures but i finally got in touch with mu mechanic friend and he is pretty sure its the cat. I was quoted 1730 from the dealership to the get new cats installed lmfao . So i will be doing the work myself learning Any advice is greatly appreciated. How to I test for sure it is the cat? Do i replace both? Will after market ones pass smog? best ones i should buy? Get a better whole exhaust? thoughts?

Smarly

yes i am guilty of running out of gas maybe 5 or six times in the last 5 years

98_3RZ

from my experience buying an aftermarket cat, and from talking to my supervising technician at the dealership. stay away from aftermarket cats, they'll work, but i put one on my 2.7 tacoma 11 months ago, and it started throwing p0420 codes last january. it started off as one every 2 1/2 weeks, then one a week, then 3 a week, next thing you know, i clear it and two trips later, the light is back on, so i just stopped clearing it. thats what i do, but from what your saying, i think you should stick with factory toyota parts