luizajeff

It started happening on the way back from CA (7stock). While driving, the car runs fine but during idle, and when hot, the car will start to run rough, back fire, and then die. Immediate restart yields nothing. After 15+ mins of cooling, however, the car fires right back up and off I go. All eng. readings are normal and coolant temp in the 80's. I have since checked the plugs and no carbon build up and I plan to do a compression test, otherwise, I am stumped as to what it could be. Outside temp does not seem to be a factor though because it happened in warm and cool outside conditions. Lose of compression, fuel injectors, fuel pressure, fuel vapor, fuel regulator, I don't know? Any ideas or those with similar problems fixed please provide info.

FDjunkie

If heat is truly a component of your problem, then the faulty item must heat and cool-down very quickly. This makes me think of igniter or coil type issues. You might try a clip-on style timing light and check each plug wire for spark while the engine is hot and not running.

wReX

iTrader: (6)

Agreed, are you running any aftermarket ignition amp?

I am having the same exact problem, but I suspect my leading coil is the culprit.

luizajeff

Stock coils. I will include them in my troubleshooting. Thanx

tman6508

My dads car just started doing a similar thing. When we drive it it runs fine at first, then after we stop at a stop sign or stop light it acts like it is stalling out when we take off. The car keeps trying to cut off for awhile and then it will run fine until we stop again. We have had it for 2 years now, and didnt have any problems until after we took it to Rotary Performance. We took it back there the day we picked it up because it started this. Brett reset the fuel sensors and the car ran fine for awile. this was a couple months ago, and it just started running bad again.

luizajeff

Well I haven't done a compression test yet but I plan to soon. If anyone comes up with a solution or sources the problem please post it or PM me / us. thanx

luizajeff

Hey, those of you with similar prob please make a note of any mods or is stock. I'm also thinking it could be a bad O2 sensor but we'll see. (Any other sensors that adjust for AFR's on the car?)

wReX

iTrader: (6)

Will it run bad, backfire, or die when you are say driving on the highway at speed? ...or is it more when you are in traffic and not getting any airflow. Does your Tachometer act wierd sometimes? I say that because it reads from the leading coil.

wReX

iTrader: (6)

I dont think it will be your O2 sensor.

To answer your other question. I am running 2nd Gen T2 coils with an MSD6A ignition amp.

luizajeff

Only at idle and when the car is hot (or well warmed up) but not hot in coolant temp. Slow traffic conditions too but runs great at cruising or accel. speeds. The tach is not acting wierd and all gauges and Commander reading appear normal. I'm going to get a new O2 sensor anyway. The one I have has at least 6K miles on it and most likely much more. It's just strange how it starts normal when cold or after the car has sat for a little bit (20+mins) after it stalls. The stalls come a little after the back-firing begins. That's why I was thinking that it slowly gets richers as it heats up and then bogs down and dies.? Still working on it though.

tom_marsland

I'm thinking ignition coils.. I doubt your o2 sensor is the culprit.. but we'll see , won't we?

wankelrx

Mine was doing the exact same thing. The problem was the Throttle Position Sensor apparently these drift over time and need to be readjusted. Follow the procedure in this post https://www.rx7club.com/forum/showth...highlight=idle

mad_7tist

why do you have the pfc on o2 feedback anyway?

luizajeff

The PFC does show voltage but it doesn't appear stable. I figure I'll replace anyway because their not to expensive. I'll check the posted thread link too. Thanx

PandazRx-7

iTrader: (18)

Doubt it's the O2 sensor. I had a very similar problem but on stock ECU...after going nuts for two weeks I figured out it was the water thermosensor. Only happened after the engine came up to a certain temp and only happened at idle or low rpm. It's behind the water filler neck and it's less than $30. Hope that helps.

luizajeff

Thanx, I'll replace and test.