95-97 Tacoma 2.4 struggle to accelerate from a complete stop issue

Recently my 96 Tacoma 2.4 2rz has been having issues with acceleration from a complete stop. It will hesitate between 100 to 1400 rpm or about 3-4 sec boggling as if it's dying B4 it would catch up and accelerate.

I have replaced the IAC value because the sensor went bad, New bank1 upstream O2 sensor, new fuel injector, new coolant temp sensor, new thermostat, new air temp sensor, New MAP sensor, checked for low oil and coolant level, change some bad vacuum hoses, new fuel filter, new PCV, Air filter, Distributor Cap & Rotor.

The code I was having was P0172. After I install the new O2 sensor it went away but after testing the vehicle around the parking lot it was still having the struggle of acceleration from a complete stop.

I have already checked for a vacuum leak with a smoker (nothing, just a small smoke that came out from the EGR vacuum solenoid filter) & test all of the new fuel injectors. The resistance was all @ 12.8 ohms across.

One assumption of what could be a possible issue is that the fuel injector holder (part#90561-10018) could be bad because the rubber is hard and could not be sealed well, allowing additional air to come in.

The second assumption could be just replacing the whole Distributor because the magnetic and wire inside could be crack & old according to a form I read (the ignition coil looks good, no sign of wear).

The Third assumption could be with the TP sensor because of the new parts but I wouldn't know how to start adjusting it (4 wire plug).

Any help guy of what my issue could be? Any help would be greatly appreciated.

 

Have you cleaned the Throttle body?

 

Thanks for the response Black Dog Lila. Yes, the Tb was clean when I replaced the IACV. The vehicle idles around 870-920 rpm roughly and when put in Drive or Reverse, it idles around 640-710 rpm.

 

Have you read live fuel data on an OBDII Scan tool?
LTFT & STFT numbers might help with diagnosis.

 

Did a scan tool test and I'm running -20%. So, tomorrow I'll be putting my old injectors back in to see if there is any difference. The OEM injector has a higher resistance of 14.7 ohms on all four injectors. My theory is the new injector might be running at a lower fuel flow rate which doesn't match with the vehicle. I'll update it tomorrow.

 

My (3.4) Tacoma was still my wife's Tacoma back in 2002 right before we were married. It began to run rough, had low power, and was missing on at least a couple cylinders. It began gradually and got worse fairly quickly. She took it to a Toyota dealership and it was showing the P0172 among a couple others, including multiple misfire. They replaced an O2 sensor and something else and it didn't solve anything. Having grown up in my dad's repair and body shop, I figured I'd better see what they missed.

It didn't take me long by going back to the basics. I pulled the coil packs, saw that all three of the rubber boots were cracked and corona-hazed at the bottoms. I was 99% sure I'd found my huckleberry. To test, I wrapped several layers of electrical tape around the bottoms of the boots and put it back together. EUREKA! No misfire and ran like a new truck. I cleared the codes and they didn't come back for a couple months. When the signs of misfire appeared again, I pulled the packs again, applied new tape, and it ran well again.

Since I couldn't find new insulator boots, I was forced to buy three new coil packs at $92/each so I wouldn't have to keep renewing the tape every couple months! I've still got the old packs out in the shed because they were still fine. Just the boots were bad.

Many times since then, I've worked on my own vehicles and customer vehicles that showed a code that was NOT the root cause of the problem.

The first thing I would do is check the openings on the boots on your ignition wires for cracks and white hazing before buying any more parts. I would also confirm correct resistance on the wires. If you've already replaced your ignition wires, please disregard.

 

I would do a compression test on all 4 cylinders wet and dry.

 

Alright, today I installed my OEM injector back in and check on the spark and wire. The wire doesn’t sit flush to the valve cover and the spark plug has some dry wet fuel on it.

So, after doing some quick cleaning and re-installing the old spark plug back in, the car was not hesitating or stumbling as bad. I made an order for a set of new ngk spark plugs and a Napa spark plug wire. I’ll install them tomorrow after work & update my outcome. Thanks for the help.

 

Update. Got the new parts in and installed. Hooked up my scan tool and ran the vehicle around town and the hwy for roughly 20min with. Today temperatures outdoor was 93 degree. Finally, No more check engine lights, struggle from a complete stop, & engine death after warmup.

This whole journey with this taco started with the “die in the heat after warm up” issue.

Helpful replacement parts that slowly lead me to resolving this issue is:
1. Replace IACV - malfunction after testing
2. Replacing the ignition igniter
3. Replacing the spark plug, wires, caps, & rotor. Hopefully this also helps other taco owner with this issue too.

Thanks Tacomaworld friends for helping me to diagnose and resolve my issue.

 

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