Engine hesitation...

My 1996 Tacoma 2.4L has 157K on it and engine seems to idle fine, but has intermittent stutter/hesitation when accelerating and cruising on interstate. I've read about TPS issues, but not sure if this is what I have or not. I went thru drive thru car wash and drove in rain, and seems to run better. How would moisture affect the TPS or is it something else? I just got it, and service records indicate a tune up (plugs and wires) in last 3k mi., new MAF 2 yrs ago and, so I'm kinda lost on this. It's my first Toyota so any help is appreciated. Thanks.

 

Is it throwing any codes?

 

CEL isn't on.

 

^bump^ changed spark plugs, went with OE NGK plugs and did the Seafoam spray in the throttle body, it smoked a little, but not much. It idles a little smoother though. I still have the intermittent miss on acceleration and with cruise set on highway. I'm not sure if it's ignition or fuel issue here. I can tell there's slight improvement, but maybe it's just me..

 

I've been troubleshooting this for a few days now and it seems to run pretty good when engine is cold, and starts the "hiccup" when it warms up some. It also happens mostly around the 2200-2700 rpm range. I've read about the TPS, any ideas on if this could be the culprit? Thanks!

 

I've been having what sounds like the same problems for the past 3 months and have chased everything. I can't figure it out. Threw a cel on Jan 1st for misfire and lean on bank 1. Plugs replaced, a couple vacuum leaks found and fixed. Continued to have stuttering, hesitation, rough low idle, rough starts. Here's what's been done so far. Would love to hear if you found the problem or if anyone has any direction to point me in. Mines a 98 2.4 with 220k miles. So far, have replaced plugs and wires twice, cleaned throttle body, out of body injector cleaning, fuel filter replaced, normal oil change done, MAF replaced, IAC valve cleaned, pcv valve replaced, new battery, TPS replaced, o2 sensors tested working in proper range, coolant temp sensor tested working. I don't know if this is fuel or alternator related but we have testes just about anything we can. No cel comes on. Fuel pressure reads at what it should according to mechanic. Help. I'm about to cut and run on this truck but I've had it for 14 years and don't want to give up on it.

 

I have a 2.4L with about 149K and my engine hesitates every 5-20 seconds only after It warms up.

The initial problem started one day while I was parking my truck when my engine just quit. After that I couldn't get it started at all. I had it towed to a mechanics shop, where they found the problem was a burnt ignition coil which in turn knocked out my igniter module. They replaced both, but it still would not start. I had an MSD ignition system which had to be taken off and it started right up. It didn't hesitate before it stopped working, but when I got it back it started hesitating. They went back over everything they had worked on and nothing was left undone. I Changed, cleaned, and replaced a lot of stuff, but still isn't running right.

I've changed plugs, wires, cleaned MAF and K&N Filter, replaced Ignition coil, Ignitor module, replaced TPS, Checked fuel system, everything is working, replaced PCV valve, O2's are working fine, and checked little things here and there. There's nothing wrong with CAT output either.

If anyone has a solution please tell me cuz it's driving me and my mechanic insane. Thanks

 

I have the exact same problem as you and almost the exact same milage (I'm currently at 147K). As you said, once it's warm it will hesitate every 10 seconds or so, and sometimes when accelerating at low RPMs I can feel it sputter.

Were you ever able to find a solution? I've already replaced the plugs, coils, cleaned the MAF and throttle body, and run Seafoam through the vacuum hose. No luck.

 

Has anyone checked the coolant temperature sensor. It affects timing when warm.

 

I'm going to pick up a multimeter and test it this weekend.

 

The way I checked it was remove it and heat up some water to about 180 and check the sensor while you hold it in the heated water. Then let it cool to ambient temperature and check it again.
Write down those values and cross reference them to an FSM or other trusted manual.

 

I hear knock sensors wear out, too but I could be wrong

 

Although true it seems the problem is when warm/hot. Coolant sensor affects ignition timing and fueling. Anything is possible though.

 

With the engine idling tap the maf lightly with the handle of a screwdriver and if the idle fluctuates the maf is bad, I hear but I could be wrong. Good luck!

 

That is entirely possible. Not sure if the 2RZ has a thermistor (IAT) built into the MAF but if so tapping it won't do a thing if it does.

 

I should have realized this earlier, but my OBD reader is able to give live statistics on the engine. I hooked it up and let the car warm up while monitoring everything. ECT is probably fine since the engine temperature reading started at 60 F and leveled off around 185-190 once warm.

I don't have values to compare my MAF readings too, but the air flow rate seems to increase steadily as I apply throttle. Which leads me to believe that it's working properly as well.

I also checked the O2 sensor readings. When idling the sensor read 0.7 V, and giving it throttle caused the voltage to jump around between 0.2 and 0.9 V. From what I read online this seems normal.

So now I'm back to square one and have no idea what's causing the problem.

 

I'm having same problem. Changed fuel pump, plugs,wires, cap and all that. Changed both o2 sensors and converter. Truck misses on acceleration and cruising speed. Seems to be worst when warm. Some one please help.

 

Have any of you all checked your distributors? I had the same issue as all of you. Did everything you all have tried. Finally replaced the distributor and it fixed my issue.

 

Have you checked the wiring harness for any chafing or bare spots?

Could possibly have a bad fuel pump or injector causing the issue.

 

I have the similar issue! I have a 1995 2.7 4x4 Tacoma and sputters around 2k-2500 rpm. I just rebuilt it and changed or checked everything but distributor. How can I test the distributor?