Rough Idle / Misfire after plugs and wires

[Gull81]

Hello all,

Looking for help regarding my 1997 SR5 V6. I recently changed the plugs and wires (Denso Plugs NGK wires). While I had the air intake off I cleaned the TB, and decided to clean the MAF. Stupidly, I used ether (starter fluid) to clean it. I have the old MAF (197400-0040).

Then, while I started the car again I noticed the idle was a bit low, would stutter, and exhaust was not smooth. The car did not throw a CEL or codes. I unplugged the MAF, and the rough idle went away. I cleaned the MAF again with MAF cleaner, no help. Seems I pissed it off good. However, when I run diagnostics, the MAF seems to behave (Around 9 grams at cold start, and 3.9-4.4 ish during warm idle).

I also unplugged the battery when I did plugs and wires, and haven't driven it much since, so I am thinking it may need to re-learn idle? I have let it warm up in idle a couple times, but have not driven it under load much.

Now, I understand I am a moron to begin with for messing with the MAF (lesson learned). But I don't want to throw parts at it unless I can be sure it is, in fact, the MAF (Since it seems to be working on diagnostics). Anyone have any suggestions on testing the MAF, or experience with this issue. I had a OBD reader, tourque pro, multimeter, so I can run the tests needed.

 

[sweet88gt]

I don't have much to offer but I do feel your pain.

At warm idle mine reads about 5 g/s. Not sure if that helps any.

At start up around 9.4 cold g/s

 

[sweet88gt]

I just ran mine around the block hot and it idled around 6-6.4 g/s just now

 

[brillo_76]

When you clean the TB and MAF. You have to be careful. Your learned a valuable lesson.

When I cleaned mine it had a high idle for 3 days. This is the TB I used MAF sensor with MAF.

So its possible you damaged your MAF sensor..


Do you have the ability to see the data off the MAF to see if it's working properly?

Sent from my SM-J337V using Tapatalk

 

[Gull81]

When you clean the TB and MAF. You have to be careful. Your learned a valuable lesson.

When I cleaned mine it had a high idle for 3 days. This is the TB I used MAF sensor with MAF.

So its possible you damaged your MAF sensor..


Do you have the ability to see the data off the MAF to see if it's working properly?

Sent from my SM-J337V using Tapatalk

It seems to be working properly, I have a Bluetooth OBD reader. The MAF reads around 4 when warm and 9-12 at cold start. Fuel trim seems normal, but it's hard to tell because they seem to reset with the battery.

However, with MAF removed, the idle is fine so I don't quite know what to think.

I just ran mine around the block hot and it idled around 6-6.4 g/s just now

From what I read somewhere else, that may be a touch high, but again you probably should take advice from me on this haha.

 

[brillo_76]

If everything is reading properly you sure you dint have a vaccuum leak somewhere?

You said you had the intake off. Are you sure your intake is resealed.

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[anormalflame]

Did you pull the TB when you cleaned it?

 

[mtbtim]

A common error people make when cleaning the throttle body is they spray a bunch of cleaner in there and guess where the dirty runoff goes? It drains right down into the IAC. If you didn't mess up your MAF with that starter fluid, I bet your IAC is gunked up. Pull the throttle body, remove the IAC and clean it out - with throttle body cleaner.

<iframe width="560" height="315" src="https://www.youtube.com/embed/agIRNNA-6cs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>


Another possibility is you didn't get the wires routed right.

 

[Gull81]

Did you pull the TB when you cleaned it?

No, I didn't pull the TB. I may do it to clean the IAC though.

If everything is reading properly you sure you dint have a vaccuum leak somewhere?

You said you had the intake off. Are you sure your intake is resealed.

Sent from my SM-J337V using Tapatalk

I re-attached all the vacuum lines. Some were cracked and I used electrical tape to tape them up before re-connecting. I pulled the vacuum lines while the car was idling to check, and the short term fuel trim shot up, so I assume that is not the issue.

 

[Gull81]

A common error people make when cleaning the throttle body is they spray a bunch of cleaner in there and guess where the dirty runoff goes? It drains right down into the IAC. If you didn't mess up your MAF with that starter fluid, I bet your IAC is gunked up. Pull the throttle body, remove the IAC and clean it out - with throttle body cleaner.

<iframe width="560" height="315" src="https://www.youtube.com/embed/agIRNNA-6cs" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

Yes, I should do the IAC next: I need to order the gaskets and a JIS screwdriver to do that. The only thing I wonder is that if I unplugged the MAF and the problem went away, could it still be that the IAC is not functioning correctly?

I guess unplugging the MAF fixing the problem at least point to the fuel and spark being alright. I checked all the wires - they are routed correctly.

Side questions: does anyone know if there are any custom PID's to use to check misfire count with torque pro?

 

[Gongshow]

I wouldn't worry about gaskets or the JIS screwdriver. Get a philips head that fits nice and snug, then make sure that you have good pressure to crack them loose. Some Seafoam or foaming carb cleaner should do nicely. When putitng it all back together, remember, "Tight is tight, too tight is two pieces."

 

[3bears]

Throttle body is not as picky as MAF...but wiht MAF you need to be careful how you clean and what you clean with...however I will admit I was lucky one time and cleaned a MAF with brake clean.
I have not watched tims video, but I can tell you that my ICV was sticky when I first bought it, and taking it off and cleaning it is the best way. I agree, cleaning throttle body in place will drain all the gook into ICV. Again, not seeing tims video, when I had my ICV off and cleaning, I plugged it in and turned key on and off several times to make the slide rotate. Maybe tim covers that.
You might get by without replacing gaskets, my first time I got the ICV gasket from NAPA, and reused the throttle body gasket with some silicone ( forgot to pick one up and had to get it back together.) 100 k later ( at 245k) and doing lots of work ( knock sensors ) I did the ICV again with a toyota ICV gasket. And every gasket ( and hose) I hit was replaced with new.
The toyota gaskets are a crush design...they are not meant to be reused..but they are often

 

[Docholliday5645]

My 4th gen had idle problems after a new battery. It simply needed to re-learn idle. Takes 5-10 minutes. Try that before spending money/time on other troubleshooting.

 

[Gull81]

I wouldn't worry about gaskets or the JIS screwdriver. Get a philips head that fits nice and snug, then make sure that you have good pressure to crack them loose. Some Seafoam or foaming carb cleaner should do nicely. When putitng it all back together, remember, "Tight is tight, too tight is two pieces."

I figure if I am going to do all the repairs the car needs (timing belt, maybe a new maf, water pump, etc etc) I will be in the hole a good amount of $ either way. I way as well invest the extra $40 and do the job right. I tried to cut corners and that didn't work out too hot.

Throttle body is not as picky as MAF...but wiht MAF you need to be careful how you clean and what you clean with...however I will admit I was lucky one time and cleaned a MAF with brake clean.
I have not watched tims video, but I can tell you that my ICV was sticky when I first bought it, and taking it off and cleaning it is the best way. I agree, cleaning throttle body in place will drain all the gook into ICV. Again, not seeing tims video, when I had my ICV off and cleaning, I plugged it in and turned key on and off several times to make the slide rotate. Maybe tim covers that.
You might get by without replacing gaskets, my first time I got the ICV gasket from NAPA, and reused the throttle body gasket with some silicone ( forgot to pick one up and had to get it back together.) 100 k later ( at 245k) and doing lots of work ( knock sensors ) I did the ICV again with a toyota ICV gasket. And every gasket ( and hose) I hit was replaced with new.
The toyota gaskets are a crush design...they are not meant to be reused..but they are often

The MAF is driving me up the walls. Reading seem normal. I could see if I cleaned it with ether and left a residue, but cleaning it again would, in theory, remove that residue and things should be good. Unless somehow the electrical got damaged.

But again, unplugging the MAF and the idle goes back to normal- so what else would anyone thing but bad MAF? Perhaps when the MAF is removed, the car throws a code, shutting down more than just the MAF. Maybe I should look up what else is shut off once the MAF code is thrown.

My 4th gen had idle problems after a new battery. It simply needed to re-learn idle. Takes 5-10 minutes. Try that before spending money/time on other troubleshooting.

I tried that a couple of times. I think I will clean the IAC (Something I should really do anyway), and then wait until I go back to work and drive the car. If the car doesn't go back to normal after that, I will look into replacing the MAF.



On my list of things for the IAC job, I have the IAC and TB gaskets, JIS screwdriver. Anything else I should change while I am in there. I should do the valve covers, but I am not comfortable with that level of job currently.

Also, I dropped one of the 10mm MAF screws, and it has disappeared. Anyone know where I can get the MAF 10mm screws - they seem to be special with some sort of copper component to them. This is the old circular type MAF in the earlier model - I will post photos if you all want.

 

[sweet88gt]

That valve cover job isn't that bad. Collect the parts Tim has in his video and follow along.

 

[superdavebigD]

No, I didn't pull the TB. I may do it to clean the IAC though.



I re-attached all the vacuum lines. Some were cracked and I used electrical tape to tape them up before re-connecting. I pulled the vacuum lines while the car was idling to check, and the short term fuel trim shot up, so I assume that is not the issue.

Just to be thorough and sure, I'd replace those cracked vacuum lines. :thumb: