Hello, I recently purchased a 97 eclipse for my son. The car has a new re-built motor with less then 100 miles on it. The car recently had a new catalytic converter installed and came with an exhaust manifold as the existing one is cracked. The car also needs a new muffler. I had my mechanic make the repairs and come to find out the manifold that came with the car was for a turbo so I had to buy another. Anyone need a deal let me know. Anyway, when we brought the car home before we made the repairs the car would vapor lock, my son would put in neutral and it would fire right back up. I figured after we made the repairs the problem would be fixed. Well, he was driving it yesterday and it did the same thing. He said that after the car warms up the RPM’s will kind of spazz out and the car almost stops. If it does stop he puts in neutral and re-starts and it will run fine for 10 or 15 minutes and do the same thing. Since I’m no Mr. Good wrench I need some opinions on what the problem could be. Hope I didn’t buy a lemon!! Any help/thoughts would be appreciated. 4 cylinder DOHC manual tranny.

 

Welcome to the site Woodys4.
Ok, here are my thoughts. I don't think it's vapor lock as it would have him stranded for minutes at a time. I think it could be the crank position sensor since this sensor is unprotected and a common issue with the 420a and 6g73 (both used in Dodge Avengers). Another thing it could be are the relays on the firewall called the .... something that has just slipped my mind. I do have a FAQ on it in this forum though. https://mitsubishiforum.com/m_137146/tm.htm . Don't have to worry about a fourth relay since you have a manual.
The coils can cause this too if they are ready to go out on you.
I hope that helps and give us a follow-up when you get a chance.

 

OK, took it to my local mr. goodwrench. He disconnected the EGR valve and problem solved. Any thoughts on leaving it disconnected. Will it cause any adverse problems down the road? Thanks

 

EGR does one thing and that's keep the emission of NOx at a suitable level. The bonus is that it keeps engine temps "cooler" and fills in for fuel when cruising, thus it helps raise MPG. If the car is for driving around town, then you won't notice a difference in MPG nor will the motor get the benefit of running cooler since the EGR won't be used much anyhow.
So, the motor will emit the normal levels of NOx, normal temps on the engine will create seemingly higher temps (although normal without EGR), and MPG will lower. Otherwise, removing the EGR from the system is not an issue with us turbo guys just check with your local garage in case there is an emission's law that will keep the car from being street legal.

 

Oh, one more thing. If the valve is clogged with carbon and that's all that is keeping it from being reinstalled, you can easily clean it with Seafoam or any other carbon buildup remover. If your mechanic saved the part, you can easily see why the valve was keeping the motor from running as it should during cruise. There will be layers of carbon buildup which most likely caused gas flow issues and starved the motor of fuel or inert gases (in other words, the chamber was only half full).