My NSX is having intermittent mis-firing

Injector - sparkplug - coil pack - etc. - etc. - etc. Weeks is really intermittant :confused:. Got to narrow it down a bit dude. At least check your sparkplugs for differences in color or buildup. Happy Motoring!
 
You didn't mention if you got any engine lights or not, but here's a couple of items to consider.

My 91 felt like it was hesitating. Sometimes just barely and sometimes pretty severely. Sometimes the engine light would come on along with the TCS light but then they would reset just as quickly as they came on and the car would run just fine. It ended up being the VSS (Vehicle Speed Sensor) on the transmission. It was a pretty easy swap.

My 97 had very similar symptoms (hesitating and then running fine) except I can't remember if any lights were coming on. It ended up being the ignition switch. The plastic mechanism on the back of where you insert your key. Apparently they wear out and intermittently will shut down your ignition as you drive.

Hope this helps.
 
Had a similar issue in my old '91. Do you happen to drive you car in the rain? I pulled the rear most coil packs to find ... drip... drip... they were drenched in water, causing me intermit miss-fire. The coil cover gaskets were getting old causing water to pool up on top of the coil packs, lucky for me I caught it a few days after driving in a rain storm. Pulled them out and dried them put them back in and never had the problem again.
 
NSXCessive said:
Had a similar issue in my old '91. Do you happen to drive you car in the rain? I pulled the rear most coil packs to find ... drip... drip... they were drenched in water, causing me intermit miss-fire. The coil cover gaskets were getting old causing water to pool up on top of the coil packs, lucky for me I caught it a few days after driving in a rain storm. Pulled them out and dried them put them back in and never had the problem again.
Click to expand...


Yes, I have driven it in VERY heavy rain for many days.

I'll check this out.
 
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NSXCessive said:
Had a similar issue in my old '91. Do you happen to drive you car in the rain? I pulled the rear most coil packs to find ... drip... drip... they were drenched in water, causing me intermit miss-fire. The coil cover gaskets were getting old causing water to pool up on top of the coil packs, lucky for me I caught it a few days after driving in a rain storm. Pulled them out and dried them put them back in and never had the problem again.
Click to expand...

This happened to me after washing my car and not driving it for a few weeks. Take a look at the contacts between the spark plug and the coil. They could be corroded. I cleaned it up with sand paper or you could replace the coils.
 
does your car have the engine cover on?
 
Change your spark plugs and eliminate possible rust on the contact area. If it does not solve the problem check the coils and/or injectors.

Try to see if one of the spark plug has a different color to know which cylinder causes the problem.
 
The engine cover does nothing to protect the coil banks from getting wet. The water drips down from the rear window garnish. I was getting annoying misfires whenever I washed the car or drove it in the rain. I finally tracked it down, changed the spark plugs and stopped driving it in the rain and problem solved. Whenever you wash the car, you should stuff the gaps in the rear window garnish with a towel to absorb the water so it does not get on the coils and you'll be good to go.
 
Most likley a coil pac. If you have an OBD II code scanner, use it to find the missing cyclinder number. Then, I would switch the coil pac with the error code with another coil pac without an error code to see if the missing cyclinder error code number follows the coil pac change.
 
The coil packs are specific to bank. I would say change out the plugs first before investing in coil packs since its a much cheaper fix if that is the problem.
 
s14_tat said:
The coil packs are specific to bank. I would say change out the plugs first before investing in coil packs since its a much cheaper fix if that is the problem.
Click to expand...

This is the best way to start eliminating the problem. Change all the rear sparkplugs. I bet its from the accumulation of water.
 
OK, I'll do all the plugs.

I just got off the phone with NGK's USA office.

The rep said that the performance of Platinum and Iridium is the same.

The advantage of the Iridium is that it should last another 25% more than the platinum since it's a harder metal.

He said the extra $$$ for the iridium makes more sense for people that have cars where the plugs are difficult to get to and they want to save $$$$ on the frequency of changing out plugs.

Sounds pretty straight forward and he wasn't trying to spin it up and sell me on performance gains like the other guys.
 
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I drive my NSX in the rain all the time and wash it without protecting the engine - no problems. When I did my timing belt replacement in 2008, plugs and coil packs were all in good shape.

The reason water can get in the sparkplugs/coil packs is if the plug/coil cover is installed upside down. That gasket must be at the top, and all surfaces clean. As an extra precaution, wipe a coat of silicon grease on the gasket before installation.

There are numerous threads on Prime on this topic. Some have even added extra gaskets on the side of the covers. However, I have not found that to be necessary in the 10 years I've had my NSX.
 
ftuhy said:
I drive my NSX in the rain all the time and wash it without protecting the engine - no problems. When I did my timing belt replacement in 2008, plugs and coil packs were all in good shape.

The reason water can get in the sparkplugs/coil packs is if the plug/coil cover is installed upside down. That gasket must be at the top, and all surfaces clean. As an extra precaution, wipe a coat of silicon grease on the gasket before installation.

There are numerous threads on Prime on this topic. Some have even added extra gaskets on the side of the covers. However, I have not found that to be necessary in the 10 years I've had my NSX.
Click to expand...

I've pressure washed my NSX and had no problems. The last time was about 10k miles ago. Now, I'm wondering if i did install the cover upside down.
 

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