Truck shuddering at idle and acceleration

I have a 2001 tacoma 3.4L 4x4. 191,000 miles on it. 2 days ago I noticed it kind of hiccuping while at stop lights. The truck would kind of shake for a second, rpms would drop about 100 then it would be back to normal for about 5-10 seconds. When I accelerate it initially feels like it has no power and shakes a bit then when it gets up to speed it is totally fine. I turned off the AC and it seemed to get a little better but it still does it, seems worse with the AC on though.
I cleaned the MAF sensor and replaced the fuel vapor pressor sensor (threw a code a month ago) yesterday. The previous owner (bought it in November) said it was doing something similar, it threw a code and so he replaced the spark plugs. I pulled one yesterday to look, I'm a little skeptical that they are only 3k miles old.
Since owning it I replaced all the fluids, cleaned MAF sensor twice, cleaned the throttle body, replaced fuel filter, air filter, PCV and gasket. The drivers side valve cover is leaking slightly and I have the parts to fix but haven't yet.

This problem has gotten way worse in two days, I'm very concerned that I may be dead in the water soon. Any advice is greatly appreciated

EDIT///////UPDATE//////CONCLUSION

I hate it when people don't post their results, putting them here to save a lot of reading. My truck started stuttering at stop lights. Got way worse in less that two weeks to where just normal driving was getting nearly impossible. Changed plug wires, MAF sensor, and finally the coil. The coil ended up being the issue. Use an OBD2 to check what cylinder is misfiring, then swap the coil out. If the misfire follows the coil then that's the issue.

 

I think you need to replace the plug wires. Plug looks fine to me. What codes was/is in throwing? Also, it is not uncommon to get a bad plug straight out of the box. A hairline fracture in the porcelain can cause a misfire.

 

Just replaced the plug wires, the old ones were original, no change in performance. I bought 6 new plugs but didn’t install them yet. Also threw in a bottle of injector cleaner just now.
Accelorator was almost to the floor and it was gutless. Almost felt like a bogged down chainsaw.
I forgot to mention I did replace the fuel pump about 1500 miles ago

 

What are the specific codes it's throwing?

 

In the OBDII world there are many, many, many different bits of information stored in the PCM, one of them is Mode 6. Mode 6 is where all of the data that can be gathered is gathered. Misfire count may or may not be one of them. If it is and it shows the same cylinder 3/4 of the job is done just by identifying the 1 out of 6 cylinders. If you do not have a code reader with Mode 6 capability you are guessing as to which cylinder(s) are the culprit and as such you will be throwing parts at it hoping you guessed right.

This presents a second problem... who in your area truly knows what they are doing with a scan tool and can interpret what it is saying. Sure the parts guy at AutoZone can plug their tool in and show you a pending code and lets say it is for one particular cylinder... is it mechanical, electrical or fuel related? There are many posts on this forum where guys have spent lot of $'s and lots of time throwing parts and not fully understanding what is going on. If this is you, there is nothing wrong with that, find a shop that has a tech that truly knows his equipment. You will be $ and frustration ahead of the game. Is that the dealer, that depends on who gets dispatched your truck to work on.

 

here is the code it was throwing. The CEL did turn off about two days after it threw it. I found a sensor for cheap that I held onto until yesterday I replaced it thinking it could be the issue but it got no better. Gas cap it on tight, ect.

 

Im usually super comfortable with Tacomas, torn one down to the frame and rebuilt it. I just lack my OBII reader, I sold it with my old truck. You are right though, better to spend a bit of money up front and get it fixed before replacing loads of stuff it didn't need. Figured the wires were cheap and it needed it anyways that hopefully it could have helped.

 

If I'm not mistaken, that pressure sensor is under the hood on the drivers side, where the EVAP charcoal canister is located. You can delete the EVAP system completely, but those sensors have to be working to avoid the code. I'm having trouble connecting the dots to that leading to your idle and loss of power issues.

My gut is saying your MAF is on it's way out, in spite of cleaning it. Check your MAF wiring right at the plug, right after the connector boot... still kind of a farce.

 

Fuel filters? Worth checking

 

Ordered a new OBD2 last night, should be here today at some point. I just changed the fuel filter.
Part of me was thinking a transmission issue but it probably wouldn’t be studdering at stop light if that’s the case.

 

I second your opinion garetcurry on the MAF. I would also look at long & short fuel trims on a scan tool. Should be between -10 to +10. And make sure you buy a real Denso MAF and not a knock-off looking Denso they sell in the $20 -30 dollar range on ebay. There is a post on here showing the the correct part number v.s. the knock-off.

 

This is what the OBD2 scanner said. If I step on the gas from a stop or on the highway trying to pass someone it just lags and is gutless.

 

This is the report from the drive around the neighborhood. Truck started shuttering bad on the second set of RPM rise (second stop start). 26 seconds

 

I would do this, especially since they're really easy to replace on the v6

Also your symptoms kind of sound like what happened to my 99 Prerunner back in the day when my MAF sensor was toast. Would stall at stop signs and have crappy power then go back to normal for a bit, then repeat. Until I replaced the sensor. Worth noting though I had a CEL related to the MAF sensor when that happened.

 

I copied this directly from a thread on the customtacos forum(credit where credit is due, right?):

P0450 (5VZ; 2001) Evaporative Emission Control System Pressure Sensor Malfunction
DETECTION CONDITION:
10 seconds or more after engine starting condition (a) or (b) continues for 7 seconds or more: (2 trip detection logic)
(a) Vapor pressure sensor value < -3.5 kPa (-26 mmHg, -1.0 in.Hg) (b) Vapor pressure sensor value 1.5 kPa (11 mmHg, 0.4 in.Hg)
PROBABLE TROUBLE AREAS:
- Open or short in vapor pressure sensor circuit - Vapor pressure sensor - ECM
TROUBLESHOOTING PROCEDURE:
The FSM diagnostic procedure proceeds as follows:
(1) Check voltage between terminals VC and E2 of ECM connector
Good (Voltage: 4.5 - 5.5 V): Proceed to Step 2 No Good: Check / replace ECM
(2) Check voltage between terminals PTNK and E2 of ECM connector
(2a) Disconnect the vacuum hose from the vapor pressure sensor.
(2b) Using the MITYVAC (Hand-Held Vacuum Pump), apply a vacuum of 4.0 kPa (30 mmHg, 1.18 in.Hg) to the vapor pressure sensor.
NOTICE: The vacuum applied to the vapor pressure sensor must be less than 66.7 kPa (500 mmHg, 19.7 in.Hg).
OK: (2a) Voltage: 3.0 - 3.6 V (2b) Voltage: 0.5 V or less
Good: Proceed to Step 3 No Good: Check / replace ECM
(3) Check for open and short in harness and connector between the vapor pressure sensor and ECM
No Good (wiring fault found): Repair or replace harness
Good (no wiring fault): Replace vapor pressure sensor

 

I just replaced the fuel filter with a WIX at the same time I did my fuel pump (denso) about 1k miles ago. I may have to break down and buy the MAF. I just hate throwing parts at the truck but at the same time going to a mechanic (the vet of cars) and getting charged the amount for 1 part that I could replace 4 with sucks too.

 

Buy a used MAF on ebay?. Just don't buy a cheap priced Denso. I will look up the part number.

 

cheap knock-offs on ebay are.

$102 22204-22010 Intake Meter Sub-Assembly

22204-22010. Real Denso is

$158 22204-21010 Internal Air Flow Meter

22204-21010. A real used MAF on ebay right now for $12.09 free ship and free 30 day returns.

 

I just ordered one.

$158 22204-21010 Internal Air Flow Meter

22204-21010. Hoping its that, this problem is getting expensive quick

 

Ebay? Used? I mentioned the one with 30 day free returns in the event it doesn't fix your issue. Then your not out money.