no low end power in high mileage 3.4L

My Tacoma has ALOT of miles on it and it is original except for a water pump and timing belt twice. The time that I changed the timing belt (2nd in lifetime for truck), was around 315K or so and I got the timing off just a bit. Well the truck would still run but just not as good as it was running. I drove it like that for probably 2 or 3 months and put probably around 4K or 5K miles on the truck like with it in that state. I decided to recover some mileage and power, that I would go back in there and get the timing right on it. When I had the front off and I reset the timing as best as I could using the marks on a replacement belt.

The truck ran a whole lot better and I got my gas mileage back, but the power has never been the same. My truck is a v6 automatic and when I punch it, it used to have a problem with traction, now it goes but it lags on till the rpms rise and then it kinda surges with good power.

This truck used to have a whole lot more power than what it has now. I don't think that driving with the timing off like that effected the power now since I got the timing straightened out. I had a 93 s-10, once upon a time, and drove around with the timing off on it for probably 6 months. I got a timing light, set the timing, and that truck became a power house (4.3TBI V6).

I think that the truck's sensors are just getting old. Sometimes the check engine light will come on and the truck will idle rough. Then the light will go away and the truck runs fine. Sometimes, the SES light comes on and will stay on for days, and then go off again with no change in the way that it runs.

It isn't a big deal, the truck is pretty good on gas, and I kinda need to be easy on it and not concerned with the power as long as it runs good and doesn't burn or drip anything. I was just wondering if anyone has had the same experience with theirs and what they did to fix it.

 

Might want to clean the throttle body, intake, and put a new intake manifold gasket on it and clean all the carbon build up out with some seafoam through the brake booster vacuum line.

 

First place I'd start is finding out what code you're getting. Then check filter, plugs, wires, clean TB and sensor. Check for cracked vaccum lines with carb cleaner. Change in rpm=leaky vac line.

 

I'd almost bet the code is for the knock sensor. Especially if your engine runs rough. If your timing is off then it will throw a code and retard the timing so you don't damage the engine.

 

Yeah, ide say sensors too. MAF and o2's are the ones that usually go first, and cleaning your Throttle body and seafoaming would help alot too. and then maybe the Deckplate mod and AFE filter.

 

At over 300k I would check the compression first. No sense in going crazy chasing an electronics issue that might not even exist.