3.4 missing/stumbling - Pirate4x4.Com : 4x4 and Off-Road Forum

red85runner · 07-05-2007, 08:47 AM

the 3.4L in my Taco has ran flawlessly for 127,000 miled, but now all of the sudden is running like crap. It has a miss or a "stumble" so to speak when accelerating under, and when cruising 50 or 60 barely on the throttle itll start hiccuping.

Well my check engine light is on, and i plugged it up and it says i have a Cylinder 1 Misfire. Well that Misfire could be pretty much anything correct? i Checked to see if i have spark to the plug, which i did, so then i replaced the spark plug just to be sure. then i ran a bottle of fuel system cleaner through it, which did no good. The haynes manual i have is kinda broad on troubleshooting, and im currently sorting through an online FSM, but i know yall would know where to start looking better than i would.

so possible causes could be?

Clogged or faulty injector
Timing belt slipped and now timing is off
Distributor cap or rotor (assuming it is a normal distributor? the way the ignition is on this engine has always confused me)
ECU went bad all the sudden?
PCV valve?

so any suggestions on which to start with?

red85runner · 07-05-2007, 09:04 AM

so after a little more research on other forums its looking like it would be plug wires, even though its sparking it might be causing a misfire, if it is not that then a coil pack? which is one of the things i dont really understand. Any suggestions?

tnxjjeeper · 07-05-2007, 09:04 AM

My cousins 3.4 has done that a couple of times. Try cleaning the Mass Air Flow sensor. That worked the last time. He also had the dealer do a Top End cleaning when it was crapping out a while back. Yours sounds like what his was doing.

Max Volume · 07-05-2007, 01:06 PM

Try swaping the #1 plug wire to a different cylinder, If the Misfire stays with cyl #1, you can safely assume that the plug wires are OK. If the misfire is still on cyl #1 try swapping the coil pack to a different cylinder. Again, if its the coil pack, the misfire should follow the coil pack. Oh, and clean you MAF sensor for good measure.

RangerCB · 07-07-2007, 12:43 PM

Don't forget to do compression test, could be a bad intake valve on that cylinder

aferg · 08-20-2007, 01:47 PM

The coil pack was the problem for my tacoma with the same problem.

Renaud33 · 08-21-2007, 10:23 AM

My truck has had a "surging" feel to it every couple of seconds when cruising on the highway. Doesn't happen all the time though. Or maybe not enough to be noticable all the time. A few buddies thought it was a worn timing chain/belt. Haven't replaced it yet so I don't know for sure. Perhaps if you find your wires and coil working properly you need to replace the timing chain/belt?

SinisterTaco · 08-21-2007, 03:08 PM

http://www.deserted1.com/FSM/Repair_...e/cip0300p.pdf

http://www.deserted1.com/FSM/Repair_...g5vzfe/pst.pdf

RockToy94 · 08-22-2007, 11:07 AM

O this is an easy one. my 97 taco did the same thing, turns out its just the o2 sensor. if thats not the fix i don't know what to tell you.

07-05-2007, 08:47 AM	#1 (permalink)
red85runner Registered User Join Date: Dec 2005 Member # 64095 Location: Memphis TN Posts: 27	3.4 missing/stumbling the 3.4L in my Taco has ran flawlessly for 127,000 miled, but now all of the sudden is running like crap. It has a miss or a "stumble" so to speak when accelerating under, and when cruising 50 or 60 barely on the throttle itll start hiccuping. Well my check engine light is on, and i plugged it up and it says i have a Cylinder 1 Misfire. Well that Misfire could be pretty much anything correct? i Checked to see if i have spark to the plug, which i did, so then i replaced the spark plug just to be sure. then i ran a bottle of fuel system cleaner through it, which did no good. The haynes manual i have is kinda broad on troubleshooting, and im currently sorting through an online FSM, but i know yall would know where to start looking better than i would. so possible causes could be? Clogged or faulty injector Timing belt slipped and now timing is off Distributor cap or rotor (assuming it is a normal distributor? the way the ignition is on this engine has always confused me) ECU went bad all the sudden? PCV valve? so any suggestions on which to start with?

07-05-2007, 09:04 AM	#3 (permalink)
tnxjjeeper Registered User Join Date: May 2004 Member # 30542 Location: Chattanooga, TN Posts: 539	My cousins 3.4 has done that a couple of times. Try cleaning the Mass Air Flow sensor. That worked the last time. He also had the dealer do a Top End cleaning when it was crapping out a while back. Yours sounds like what his was doing. __________________ www.rebelrockrunners.org 97 Tacoma-Duals,Tons,Coilovers,40's.... still not done

07-05-2007, 01:06 PM	#4 (permalink)
Max Volume Registered User Join Date: Apr 2003 Member # 19077 Location: Socal Posts: 2,235	Try swaping the #1 plug wire to a different cylinder, If the Misfire stays with cyl #1, you can safely assume that the plug wires are OK. If the misfire is still on cyl #1 try swapping the coil pack to a different cylinder. Again, if its the coil pack, the misfire should follow the coil pack. Oh, and clean you MAF sensor for good measure. __________________ yotamasters.com <-------- NEW WEBSITE IS HERE!!!!!

08-20-2007, 01:47 PM	#6 (permalink)
aferg Registered User Join Date: Mar 2005 Member # 45011 Location: Vancouver, BC. Posts: 5	The coil pack was the problem for my tacoma with the same problem. __________________ 77 FJ 40 90 2-door 4Runner 94 7M-GTE 4Runner :-) 95.5 Taco

08-21-2007, 10:23 AM	#7 (permalink)
Renaud33 Registered User Join Date: Oct 2003 Member # 23389 Location: Des Moines, IA Posts: 1,332	My truck has had a "surging" feel to it every couple of seconds when cruising on the highway. Doesn't happen all the time though. Or maybe not enough to be noticable all the time. A few buddies thought it was a worn timing chain/belt. Haven't replaced it yet so I don't know for sure. Perhaps if you find your wires and coil working properly you need to replace the timing chain/belt? __________________ 85' 4Runner - AP extreme lift, 37" PB Rockers, duals TLCA Member# 16265

07-05-2007, 09:04 AM	#2 (permalink)
red85runner Registered User Join Date: Dec 2005 Member # 64095 Location: Memphis TN Posts: 27	so after a little more research on other forums its looking like it would be plug wires, even though its sparking it might be causing a misfire, if it is not that then a coil pack? which is one of the things i dont really understand. Any suggestions?

07-07-2007, 12:43 PM	#5 (permalink)
RangerCB Registered User Join Date: Jun 2007 Member # 92921 Posts: 37	Don't forget to do compression test, could be a bad intake valve on that cylinder

08-21-2007, 03:08 PM	#8 (permalink)
SinisterTaco Sometimes I drink Join Date: Nov 2004 Member # 39343 Location: Alaska Posts: 201	http://www.deserted1.com/FSM/Repair_...e/cip0300p.pdf http://www.deserted1.com/FSM/Repair_...g5vzfe/pst.pdf __________________ -Thomas

08-22-2007, 11:07 AM	#9 (permalink)
RockToy94 Registered User Join Date: Jun 2007 Member # 93054 Location: Vermont/Wyoming Posts: 458	O this is an easy one. my 97 taco did the same thing, turns out its just the o2 sensor. if thats not the fix i don't know what to tell you. __________________ My Build: [URL="http://www.pirate4x4.com/forum/showthread.php?t=695669"]http://www.pirate4x4.com/forum/showthread.php?t=695669[/URL]

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode