Tk151

So I've been searching the forums and i can't find to much that is going to lead me in the right direction so I've decided to create a post.
i have a 93 pickup with the 3vze, auto tranny, and 4 wheel drive. 158k on the dash. Head gaskets were changed by toyota in 2004.

The issue I'm having is the truck is getting absolutely horrible gas mileage. i can get 120-130 miles out of a tank in the city and about 150-160 on the highway. Also when its in park and idling it runs very smooth without hesitation. when i put it in drive it starts to shake and almost feels like a misfire. Also noticed while I'm on the highway running at about 60-65mph, it doesn't want to accelerate with out me turning the overdrive off. If i go up a hill it slows down to the point where i have to turn the overdrive off. I don't expect to much out of this engine but my buddy which has the same truck has no issue at highway speeds. This problem is driving me nuts and I'm at the point where i have invested to much time and money into this truck to call it quits.

Heres a list of what I've done in the last couple months to the engine.
- New plugs
- New Wires
- New distributor
- New VAFM
- New PCV and hose
- New Fuel Pulsating dampener
- New Intake Plenum Gasket
- New EGR gaskets
- New O rings on the injectors
- New ECU
- New 02 Sensor
- New Cat
- New muffler
- New Fuel pressure regulator
- New intake And hose connecting to throttle body
- Random vacuum lines replaced that were old and cracked
- New Ground connecting battery to body
- New thermostat
- Coolant Flush
- New fuel filter
- let the injectors soak in sea foam over night.
- New Valve cover gaskets
- Checked timing, it was set at 25 or so btdc, put it to 12 btdc. made idle worse. no improvements to fuel mileage.
Im sure I'm missing some other things I've also replaced, ill add as i remember.
When i removed the plenum, the tvv broke as they usually do so i plugged the holes and ran the lines elsewhere.
I have checked my vacuum with a vacuum gage, held -20 with no issue at idle. Ive checked every vacuum line multiple times to check for leaks and have found nothing. Ive also ran sea foam through the vacuum lines and also in the fuel tank. no improvement although i didn't expect it to improve anything.
Im going to check fuel pressure as soon as possible. Ive ran the diagnostics on it and have pulled zero codes.

Ive had 2 different shops look at this truck and they can't figure out what the issue is as well.

Any input would be greatly appreciated!

Im about to roll this truck into the alley and burn it.

JasonYota

iTrader: (1)

How long has the problem been going on? Since you bought it? On the mileage, saying you get XXX miles per tank doesn't mean anything nor is it an accurate way to figure fuel mileage.
Does it only happen in drive? What about reverse? Does the idle drop or does it actually start misfiring?

Tk151

The problem has been going on since I got the truck, but when I bought the truck I knew the fuel pulsating dampner was leaking fuel so I figured that was the reasoning behind it, even after fixing that issue there was no change. And yes anything but park it will sit and shake like it's close to stalling out. Idle doesn't drop much when going from park to drive or any other gear. Hard to tell I don't have an rpm gauge on the dash. But I don't think it's actually a misfire. Both shops agreed it's not misfiring.
And I just reset the trip meter at every fill up which is basically every two days and see what I get total. I'll try to get a more accurate reading.

bswarm

If your timing was that far off maybe they didn't get the cam timing correct when the heads were done. Do a compression check and see if it matches the FSM specs.

Tk151

I'll test the compression this weekend, hopefully tomorrow and I'll post what I find out.

Bowtiebogger

Check the air intake tube. If it's split or cracked the MAV sensor downstream of air cleaner will act up and foul up the air fuel mixture

Tk151

Just checked it out and I didn't find any splits or cracks.

Tk151

Anyone think my TPS might be causing this issue?

And I haven't had a chance to do a compression test yet, my tester is currently missing so I might have to buy a new one.

I also just noticed my pcv is loose? Is it supposed to be like this? I can move it around with my finger.