shortbus75

1998 ES300 v6. it started about a month ago. I will be driving along and everything is fine. I'll go to accelerate or pass and its like the cars only running on 4 cylinders. I thought about all the basic stuff but the funny thing is that when I hit a certain throttle position( about 80%) it kicks in and pulls away like normal. I hooked up my scanner and watched the TPS and mass air sensor as i drove. They look fine. I drive 100 miles round trip to work everyday. It will come and go 2 or 3 times a trip. every now and again i can make it all the way and it wont happen.
When it happens its like the motor loses half its power. it will hardly go up a hill without having to drop back a gear. when that happens it will rev high but still not have the full power until I reach about 80% throttle position.
I changed the TPS and still same.
It also never has a power loss feeling when at low speeds like pulling off from a stop light. only when Im above around 40 mph all the way to 80mph.
I cant make it do this now but the first few times it happened i could hit a pothole and make it stop. I could also hit the pothole when it was good and make it mess up again.
I took it to a shop and it ran fine for them as they drove it for a couple days. I told them to hit a pothole or curb and try to make it mess up again but they couldnt make it happen. Now i have it back and it comes and goes

Any ideas???

LeX2K

Any codes at all? It could be something as simple as a bad connection to the battery posts.

shortbus75

Not really. I get a bad shift from the transmission but thats been there for years. I can reset it but it comes back every couple weeks. Other than that no codes.

LeX2K

Has the transmission been properly serviced over the years?

shortbus75

yes. I havnt had any issues from it yet

808mcv20l

These types of performance issues are really hard to troubleshoot if there are no codes.

What's the Maintenance level like on this car?
Spark plugs ever changed? it almost sounds like they need to be re-gapped or changed.

being a 98 you probably have 3 coil packs in the front with 3 spark plug cables that lead to the rear 3 cylinders, any damage or loose cables? How many Miles on the ignition coils? I find that coil life is hard to gauge, I've seen some go 200k+ some only 80K and started giving problems.

You tried running fuel system cleaner through it? Marvel mystery Oil or other cleaners?

shortbus75

i forgot to add that i have also changed the plugs and coil packs and wires also.

808mcv20l

it could be a bad injector to a clogged CAT, I'm reaching here at this point. I know a coworker of mine have had similar loss of power issues you were describing in a 4runner and it turned out to be a bad injector.

My Dad's 01 odyssey van had an issue where it would drive normally on the streets but when on the freeway or going uphill it would do this weird thing where it would get stuck going 40-50mph and the RPMs would lock at about 4k. The car would start slowing down no matter how much gas you give it.

We get this burning smell, pull off to the side of the road for a few mins turn it off. Start it back up and it runs fine for a bit and the problems come back.

The codes it was pulling was misfires. We replaced all coils and plugs. (no wires to change)

The culprit in this case was the Catalytic converter which was thoroughly clogged. There were chunks of metal in there and you couldn't see through it. Once replaced the car drove normally again.

fortitude

You mention "a bad shift from the transmission". Is that referencing a specific transmission trouble code? Or is it a noticeable issue you experience with the transmission?