I've noticed on the last two road trips the engine will flat spot during acceleration at about 70 mph in 5th and then after maybe one or two seconds the power hits hard. It feels like an ignition problem. The car is running iridium plugs installed 10K ago and the wires were replaced at the same time. I'm thinking map sensor. Can anyone who's had a map sensor fail please tell me what your symptoms were. Thanks.

 

Are you on speed density?

 

No.

 

Map sensor is only used for the EGR on a stock tune. Will not make it run any different if its bad.

 

Evo9's will have issues if a MAP sensor goes bad even with a MAF tune. You would need to datalog the "event" to see if the MAP flat lines when it happens.

Could be plugs or tired coils too. I replace spark plugs every 10k or so.

 

I have a MDP, not a MAP. I've read that on the latter Eclipses the MDP was there only to check the operation of the EGR. I wasn't sure on the Evo. The FSM is mysteriously silent on this topic. The plugs are iridium with 10K so they are still like new. They come out at 60K looking new. The wires are new too. It could be a coil but that would drop two cylinders on my stock rig but this is just a two second droop, not very dramatic, but not there before. Yeah, I need to log it.

 

Well, on an Evo9, they won't run if you replace the stock MAP with an Omni 4bar map. So, that sensor is worth looking into.