98 4runner runs rough.... sometimes
- Thread starter ekgguy
- Start date
Your problem is different than mine, if it is a miss you will need to diagnose if it is fuel or spark related.
Of course it could be compression as well but you would hear that upon cranking.
When it misfires does it clear itself out after it warms up or?
This is the first time the cel popped up. It did it this morning and went away about 5mins. It doesnt last no more than a couple of miles then it disappears like nothing was wrong.
EDIT: disconnected the battery at work for about 30mins. Went back and started car., drove it around for a little bit. Cel light was off and never came back on but the symptoms were still there. Misfiring and low idle at 500rpm.
EDIT: disconnected the battery at work for about 30mins. Went back and started car., drove it around for a little bit. Cel light was off and never came back on but the symptoms were still there. Misfiring and low idle at 500rpm.
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Squirt
New member
you said you replaced the plugs recently. definitely check to make sure the gap is correct.
what code did it throw?
if the plug wires have never been replaced I would definitely go ahead and replace them. as far as the coils there are a few threads on here that show you how to test them before spending money to up and replace them.
after making sure none of those parts are faulty,if that surge is still there then yes you have an injector going bad.
what code did it throw?
if the plug wires have never been replaced I would definitely go ahead and replace them. as far as the coils there are a few threads on here that show you how to test them before spending money to up and replace them.
after making sure none of those parts are faulty,if that surge is still there then yes you have an injector going bad.
Squirt
New member
I would definitely go ahead and replace the plug wires... CARQUEST has worldpac parts that are going to be exactly like OEM. but yeah do the wires and test your coils. If after driving it it still gives you the same problem you most definitely should do the injectors..I ordered mine off Amazon rebuilt Denso for the cost of what 2 new OEM would have been..
Jhelms
New member
Received my injectors back from AUS in Tempe Az today. They did not give me flow rates at different duty cycles with was rather frustrating as that is what I expected (from previous service)... I did get before and after peak flow however.. but that does not tell me crap about how fuel would flow at idle or partial throttle / duty. So basically I just know they were cleaned and fuel flows perfectly at WOT lol
Lowest injector came in at 96% of a new stock injector and the highest came in flowing over 104% or 106? cannot remember. After cleaning / ultrasonic, flushing and all that jazz they all equaled 100% to a new stock injector which is all I know right now.
I guess you have to ask them specifically for a flow chart if they are not considered "performance" injectors. Lessor learned - nothing wrong on their part and excellent service with them as always, just expected A and received B as I did not know they had two service options for the same price.
Lowest injector came in at 96% of a new stock injector and the highest came in flowing over 104% or 106? cannot remember. After cleaning / ultrasonic, flushing and all that jazz they all equaled 100% to a new stock injector which is all I know right now.
I guess you have to ask them specifically for a flow chart if they are not considered "performance" injectors. Lessor learned - nothing wrong on their part and excellent service with them as always, just expected A and received B as I did not know they had two service options for the same price.
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Instead of just arbitrarily replacing parts, you should test things and see if you have spark at the wires ends first, then at the plugs.
If you have spark, then you know that you have a fuel issue (most likely)
The hard part of mine was that the problem only happened every once in a while - then it got worse, allowing me to figure it out.
It's tough when it is intermittent. Like I say it was easy because mine became consistently bad.
So I didnt get the change to change the wires this weekend. But I did take the 4runner on a fishing trip which was about a 300 mile round trip. It ran fine all the way back and forth. When going to work this morning, it started up running rough and misfiring. Wtf!?! Lol
CEL pops up and and starts blinking for a couple of secs. I got P0304, cyl 4 misfire
Anyone else get any similar codes?
I just ordered new coils & injectors. Since I'm gonna be doing my valve cover gaskets this weekend, i might as well get the injectors done while im in there.
I finally bit the bullet today and replaced everything.
I had been driving the truck for the last week and it was doing the same thing. Sometimes ran good, sometimes ran bad. I took it back and had the CEL ran again and it came up with a misfire on cylinders 1,3 and 4.
So, I ordered an entire set of fuel injectors, new NGK spark plugs and new wires. I replaced everything this morning and have driven the truck around the neighborhood. The CEL went out and the truck runs great.
Daughter is taking it to see BF now, so that will be the test.
Thanks for all the advice.
One thing that I did find, when I pulled the wires off, on cylinder 4 and 6, the inside of the spark plug boot that connects to the spark plug, stayed on the spark plug. It had completely come loose from the spark plug boot itself. When I finally got the ends off the spark plug itself, you could see where it was burned on the edge that goes inside the boot. I know that wasn't the entire issue, but I am sure that it contributed.
Again, thanks for all the good advice.
Matt
I had been driving the truck for the last week and it was doing the same thing. Sometimes ran good, sometimes ran bad. I took it back and had the CEL ran again and it came up with a misfire on cylinders 1,3 and 4.
So, I ordered an entire set of fuel injectors, new NGK spark plugs and new wires. I replaced everything this morning and have driven the truck around the neighborhood. The CEL went out and the truck runs great.
Daughter is taking it to see BF now, so that will be the test.
Thanks for all the advice.
One thing that I did find, when I pulled the wires off, on cylinder 4 and 6, the inside of the spark plug boot that connects to the spark plug, stayed on the spark plug. It had completely come loose from the spark plug boot itself. When I finally got the ends off the spark plug itself, you could see where it was burned on the edge that goes inside the boot. I know that wasn't the entire issue, but I am sure that it contributed.
Again, thanks for all the good advice.
Matt
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So, she just texted me said the truck ran perfect the entire way. I am going to count that as a success.
Squirt
New member
I just threw new injectors in mine today. drove it for a bit, has much more power not as sluggish. Monday I should know whether or not it took care of the hesitation at highway speeds. I drive around 150 miles a day, maybe shutting it off twice in that time frame. Mine usually would show the hesitation later in the day after it had gotten good and hot for long durations. I can honestly say I didn't realize how much power I had lost until after I put these injectors in.
I have been driving it for almost 2 weeks now with no issues. You are right though, it does have a lot more get up and go with the new injectors and now that all of the spark plugs are getting fire, makes a big difference.
Thanks,
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