Runs rough after heavy rain

[4runny]

Hey guys I need a little help here.
So I have a 96 4runner limited edition 4X4 with 172,000 miles on it. The runner runs rough when it rains out. Other then that it runs fine. I had changed the plugs and wires but it's still doing the same thing after it rains. After the engine warms up, it runs fine. It's like the engine heat dried up the moisture.

Thanks in advance.

 

[drmorbius]

Hey guys I need a little help here.
So I have a 96 4runner limited edition 4X4 with 172,000 miles on it. The runner runs rough when it rains out. Other then that it runs fine. I had changed the plugs and wires but it's still doing the same thing after it rains. After the engine warms up, it runs fine. It's like the engine heat dried up the moisture.

Thanks in advance.

Check for a cracked distributor cap, look for signs that water has been on the cap(stains). Maybe just replace cap and rotor.

 

[4runny]

Re: Re: Runs rough after heavy rain

Check for a cracked distributor cap, look for signs that water has been on the cap(stains). Maybe just replace cap and rotor.

It don't have cap and rotors.

 

[drmorbius]

Re: Re: Re: Runs rough after heavy rain

It don't have cap and rotors.

So you have the V6 ?

 

[techno]

The 2.7 and the 3.4 are both electronic ignition, hence no moving parts.

Have you inspected the air intake system? Check the filter box for water before you start the engine and check the condition of the filter while your at it.

 

[4runny]

Sorry, I forgot to mention it's a 3.4 V6.
Air intake tube has no crack. Filter was replaced 1,000 miles ago.

One other thing is after it rains and the engine runs rough, I get a code stating misfire in cylinder 6. After the engine warms up and it's running normal again, I can clear the code and it won't come back until the next rainstorm.

 

[410toy]

check all your vacuum lines. they may have deteriorated or have a leak in one or more of them, check the connections to make sure they are securely fastened. if you have to replace them, replace them with silicon lines and make sure you use new clamps to secure them in place. Also with the filter check your mass air flow sensor it may be dirty or old if their is moisture on it, it sends the wrong messages to the computer. The moisture may evaporate after your engine bay heats up and or fresh air drys it off. while you have the filter box out (it also only takes about 10-15 to take out) you may want to do the deck plate mod and get some extra power. I have done the deck plate mod and have been very very very happy with the results. what kind of filter did you put in your 4Runner? Also you may want to look under your 4Runner and check out your exhaust system if it has a lot of corrosion around the air fuel ratio sensor and or oxygen sensor you may want to replace them if you never have before your 4Runner has a lot of miles on it. You can get a great deal on them at URD.com call them and tell them you are a member of T4R.org and a member recommended you they will take care of you I have bought my sensors from them. As far as changing the sensors when they start to go bad they have trouble working until the vehicle has warmed up. Just some suggestions hope it helps

 

[4runny]

check all your vacuum lines. they may have deteriorated or have a leak in one or more of them, check the connections to make sure they are securely fastened. if you have to replace them, replace them with silicon lines and make sure you use new clamps to secure them in place. Also with the filter check your mass air flow sensor it may be dirty or old if their is moisture on it, it sends the wrong messages to the computer. The moisture may evaporate after your engine bay heats up and or fresh air drys it off. while you have the filter box out (it also only takes about 10-15 to take out) you may want to do the deck plate mod and get some extra power. I have done the deck plate mod and have been very very very happy with the results. what kind of filter did you put in your 4Runner? Also you may want to look under your 4Runner and check out your exhaust system if it has a lot of corrosion around the air fuel ratio sensor and or oxygen sensor you may want to replace them if you never have before your 4Runner has a lot of miles on it. You can get a great deal on them at URD.com call them and tell them you are a member of T4R.org and a member recommended you they will take care of you I have bought my sensors from them. As far as changing the sensors when they start to go bad they have trouble working until the vehicle has warmed up. Just some suggestions hope it helps

Ok, I'll check all my vacuum lines and MAFS. Oxygen sensor before and after that cat has been replaced already.

 

[4daRUNNER]

you say the code is a misfire on cylinder 6 ? you might wanna check your cylinder 6 Coil Pack. i know it has nothing to do with the rain and all but, if its throwing you that code then i would definately check it out. i replaced my cylinder 5 Coil Pack after similar problems (without rain) and cleared when the 'Runner warmed up. i also replaced wires and plugs. hope this helps any.

 

[4runny]

you say the code is a misfire on cylinder 6 ? you might wanna check your cylinder 6 Coil Pack. i know it has nothing to do with the rain and all but, if its throwing you that code then i would definately check it out. i replaced my cylinder 5 Coil Pack after similar problems (without rain) and cleared when the 'Runner warmed up. i also replaced wires and plugs. hope this helps any.

Ok so this might sound kinda stupid but how do I know which one is cylinder 6?
If I'm standing in front of the engine bay,
how do I determine which one is it?:help:

 

[4daRUNNER]

4runny, PM sent

 

[4wheeln98]

Hey, mine does the same thing, started bout a month ago. When it rains or when its really humid out. Rough start (shaky) and flashing check engine when driving. Had my plugs checked and they are fine, but do have original wires if that may cause it. Did you figure out what exactly is the problem was?

 

[4runny]

Hey, mine does the same thing, started bout a month ago. When it rains or when its really humid out. Rough start (shaky) and flashing check engine when driving. Had my plugs checked and they are fine, but do have original wires if that may cause it. Did you figure out what exactly is the problem was?

No I haven't. It only happen during a heavy rainstorm like when it rain all day. We had rain but nothing major so it didn't act up. I bought the electronic ignition for cylinder 6. I didn't put it in yet until it acts up so I know for sure that it was the problem.

I'll keep everyone posted if it fix the problem. If you happen to fix your problem before I have a chance to, post your results.

 

[4wheeln98]

just had a tune up done on mine after a while with it running ruff(after rain and humid days). It then started acting up more often. Well replaced wires, plugs and two of the coils. Its running fine now and problem fixed. Check the direct coils if you havent already.

 

[wrightvh]

Rough idle after rain

Did anyone else experience/resolve this issue? I have a 98 v6 and am experiencing the same problem...

 

[MOFO_Runner]

'97 4Runner Limited V6 - It would have hard starts and rough idle/acceleration on humid/wet days. It would go away when warmed up. In the final stages (last couple days) it had a surging idle. Normal high idle then drop down, then surge for 30 seconds or so, then drop down again. It finally stopped starting (wait, whaaaat?) altogether. There were just a couple hard starts then it just wouldn't start without a lot of cranking and luck, totally unreliable. The fix for me was using carb/choke cleaner on the MAF, Throttle body (TB) and TB metal shim/gasket, and IAC. The TB shim was horribly varnished but cleaned up with some elbow grease. After a couple semi-hesitant starts it's been running like a champ. I tentatively drove it to meet up with some friends and it poured rain while we were hanging out. I was nervous but it started up, no hesitation and got me home no issues. It's been raining through the night and it starts up like never before. Total cost = an extra large can of carb/choke cleaner on sale for $3.?. Good Luck, I hope this helps someone.
-MOFO
EDIT: So it ran okay for a day then started surging and hard starting again, almost stranded me. Changed the spark plugs an wires and it helped but did not fix. I was @ 50K miles on them anyway. Changed the Throttle Position Sensor (TPS) and it starts so much easier and seems back to normal.

 

[jsukey]

Had the same issue, and it was one of the coils.

 

[SpidermanGeek]

Mine just started doing this as well (97 Limited 5VZFE). I'm hoping it's wires/plugs and/or Ignition Coils.

No codes are being thrown (yet), but she has a stutter when I first start-it up after some rain or heavy morning dew.

It goes away pretty quickly right now once the engine starts warming up a little. I only need to drive it a couple of miles before it clears up, but I know this is probably a sign that a part is on its way out.

I'll start with the wires and Plugs. I know the wires aren't OEM because they're blue (replaced by Previous Owner I would assume). If that doesn't solve it, I'll have to move onto plugs and then possibly try and determine which coil pack may or may not be on the verge of failing. Maybe I'll be throwing codes by then and that'll give me a clear direction.

 

[Sil4runner]

Anyone have an update on how they fixed the issue

 

[T4R2014]

If plugs and wires don't fix it, then it's ignition coils in my experience. TBH the ship has sailed on most original ignition coils. Even if you aren't throwing misfires you will get better performance and reliability with some new Denso coils.