Do too a medical emergency for a family member, I have been driving my 2001 LX a lot on the interstate for the past 3 weeks. I have noticed from at random times at 70mph or more the engine feels like it suddenly loses approximately 25% of its power. When it loses power, I feel no shuttering, no noises, no weird smells or extra vibrations in the gear shift lever. The engine has not died or left me stranded.
I bought it from the original owner with 107,000 miles and it currently has 130,000 miles with no check engine light or codes. Has been approximately 70f to 80f, high humidity, sea level, flat interstate and AC on. Tried all different grade fuels from different stations. From 87 octane to 93 no-ethanol. Mostly has happened at dark but, I have been doing most of my running at dark.
The power loss normally doesn't happen until after 30 minutes into my trip. Trip is normally between 1 to 1.5 hours.
Work performed on it in the last 20,000 miles (so I assume these aren’t the problems):
1.) Replaced all 8 spark plugs with Toyota long life plugs.
2.) Replaced all 8 coil packs with Denso
3.) Replaced the MAF sensor with Toyota (because I was randomly having an engine stalling problem when accelerating from a stop. No engine codes but, the Toyota dealership finally determine it was a slow to respond MAF sensor)
4.) Replaced the 2 upstream O2 sensors with Denso
5.) Replaced idler pulley with Toyota (because the pulley was making a grinding noise)
6.) Replaced alternator with a 250a DC Power Alternator (because I have high power stereo system)
7.) Replaced starting battery
8.) All fluids have been changed (oil, transmission, chunks, transfer case, brake fluid & etc.)
9.) Timing belt changed.
10.) Air filter changed
11.) Fuel filter by the engine changed with Toyota filter.
12.) Fuel pump & sock in the gas tank changed with Denso.
13.) Induction system was been cleaned by Toyota dealership.
14.) AHC fluid and globes have been changed.
15.) Drive shaft has been greased.
16.) Front and rear brakes and fluid have been serviced and changed.
17.) Washed the outside of the radiator & changed anti-freeze.
18.) Valve covers are not leaking and have been retorqued.
19.) No noticeable exhaust leaks.
20.) Gas cap replaced with Toyota cap. No hissing or gurgling when I stop to refill. I normally don't get below a 1/4 of a tank either. I never overfill either.
What I haven’t done that might be causing my problem:
1.) Cam sensor (probably original)
2.) Fuel injectors (probably original) (other than running BK44 & seafoam fuel treatment through it after the problem began)
3.) Anything to do with the Cats, Charcoal filter and exhaust system (probably original)
4.) Downstream O2 sensors (probably original)
As you can tell, I don’t mind spending money on my baby because I plan on keeping her forever and I don’t mind light wrenching. I also know the parts are 20 years and would like to replace anything that might fail but, with my time being limited right now, I don’t want to spend time just replacing random parts.
So does anyone have any suggestions on what might be my problem? If so, I would appreciate it!!
I bought it from the original owner with 107,000 miles and it currently has 130,000 miles with no check engine light or codes. Has been approximately 70f to 80f, high humidity, sea level, flat interstate and AC on. Tried all different grade fuels from different stations. From 87 octane to 93 no-ethanol. Mostly has happened at dark but, I have been doing most of my running at dark.
The power loss normally doesn't happen until after 30 minutes into my trip. Trip is normally between 1 to 1.5 hours.
Work performed on it in the last 20,000 miles (so I assume these aren’t the problems):
1.) Replaced all 8 spark plugs with Toyota long life plugs.
2.) Replaced all 8 coil packs with Denso
3.) Replaced the MAF sensor with Toyota (because I was randomly having an engine stalling problem when accelerating from a stop. No engine codes but, the Toyota dealership finally determine it was a slow to respond MAF sensor)
4.) Replaced the 2 upstream O2 sensors with Denso
5.) Replaced idler pulley with Toyota (because the pulley was making a grinding noise)
6.) Replaced alternator with a 250a DC Power Alternator (because I have high power stereo system)
7.) Replaced starting battery
8.) All fluids have been changed (oil, transmission, chunks, transfer case, brake fluid & etc.)
9.) Timing belt changed.
10.) Air filter changed
11.) Fuel filter by the engine changed with Toyota filter.
12.) Fuel pump & sock in the gas tank changed with Denso.
13.) Induction system was been cleaned by Toyota dealership.
14.) AHC fluid and globes have been changed.
15.) Drive shaft has been greased.
16.) Front and rear brakes and fluid have been serviced and changed.
17.) Washed the outside of the radiator & changed anti-freeze.
18.) Valve covers are not leaking and have been retorqued.
19.) No noticeable exhaust leaks.
20.) Gas cap replaced with Toyota cap. No hissing or gurgling when I stop to refill. I normally don't get below a 1/4 of a tank either. I never overfill either.
What I haven’t done that might be causing my problem:
1.) Cam sensor (probably original)
2.) Fuel injectors (probably original) (other than running BK44 & seafoam fuel treatment through it after the problem began)
3.) Anything to do with the Cats, Charcoal filter and exhaust system (probably original)
4.) Downstream O2 sensors (probably original)
As you can tell, I don’t mind spending money on my baby because I plan on keeping her forever and I don’t mind light wrenching. I also know the parts are 20 years and would like to replace anything that might fail but, with my time being limited right now, I don’t want to spend time just replacing random parts.
So does anyone have any suggestions on what might be my problem? If so, I would appreciate it!!
