Hey guys, new to the forum.

I can't seem to find any threads on my problem. The car has had the IACV replaced 6000km ago, and was running great up until yesterday. I started it, it sounded off. It is very wet outside. I drove down towards Brampton and as I got on the highway it threw P1129 code (MAP higher than expected) and hesitated badly. When coming to a stop the idle is very low (400+/-rpm) but recovers within 5-8 seconds to around 720-760rpm. It was very wet outside, and plug wires were original so I replaced- to no avail. The car also has a bad raw exhaust smell (I think it has a slight manifold leak). Any ideas? Could it be the distributor? Plugs are also new. At higher engines speeds it seems to run fine, but will hesitate occasionally even then. Starts right up with no excessive cranking.

 

Several years ago Honda had problems with Accord and I "think" Civic MAP sensors throwing codes due to moisture in the sensors. I seem to remember the replacement sensors also had a different design connector that required removing and changing wire positions.

 

Thank you for the reply! I will look into this. I am almost certain that it is weather related as the car was perfect until the other day when I started it in the pouring rain and super high humidity. I think moisture in the distributor might also be playing a role but Im not sure. Could be a combination of many things.

 

Its not map related. If the sensor was bad for whatever reason, it would read lower, or wouldn't read at all, but not higher.

Why not remove the distributor cap and inspect the wear on the contacts and rotor? 3 little (6mm?) Bolts and cap slides off.

Though I doubt its that. Take a look at you throttle body. I think its safe to say its cacked in carbon isn't it? Try cleaning it. Should fix the problem.

 

Now we're getting somewhere thanks. the throttle body was cleaned when I did the IACV in December, BUT I will check this out. I will start with the distributor. Any idea what sort of condition will throw that code on the map sensor? The other thing I should mention is it does throw the "O2 sensor slow response" code periodically, but hasn't recently. This all started on a very wet day so I'm thinking it is ignition related still, but I am not stuck on this idea. Thanks for the input!

 

All that honda manual says is, check map sensor with scanner to read the vacuum. If its beyond certain values, replace the sensor.