so b4 winter my car would occasionally misfire for a split second, now that it cold outside my car has been getting worse..... cold start good, runs fine til engine temp is 100 degrees, once its there, it runs like ****, misfire studder. but will get moving if i stomp it, but still runs like crap until its almost fully warmed up. a couple times iv killed it and catch a wiff of fuel (every great once in awhile)
i hit the search up first but it does not like me.
any help would be greatly appriciated

 

First things are essential.

CHTS(cylinder head temp sensor located between #6 & #5 sparkplug)
MAF(mass airflow sensor)
Dizzy timing
Fouled plugs
Good injector plugs(to include CHTS plug)
Clean Fuel Filter
Vacuum Leaks


Check them then well digg into the bigger stuff

 

Then if those don't solve your problem. Try checking the TPS (throttle position sensor, and the ICM (ignition control module)

 

well im convinced it is temp related. it runs great cold and also warm, its just the inbetween. new injectors, plugs/wires good, oh also i can sometimes fix it instantly if i tach it out to six or rev it hard a few times
thanks for your help guys

 

i know that this is kinda the wrong place for it but i wanted to brag somewhere, my car is famous lolhttp://www.thezstore.com/page/TZS/PROD/7FAD/50-1444
btw my new avatar hasnt loaded but the blue one is mine

 

Still have a running issue but lately it only runs good cold and runs badly warmed up. Wth? BTW, it usually idles fine

 

change your chts. cheap and easy. check the wiring and the connector. clean afm, ecu and tps connectors with deoxit. problems running hot or cold and not when opposite almost always are the chts.

 

I'm seeing an almost identical problem on mine right now, working on tracking it down now. Also noticed a big drop in fuel mileage, which could be related. (was 23mpg, gotten 17, 17, 17, & 16 on my last 4 tanks, all highway. Weather is obviously colder which makes a difference, but it shouldn't suffer that much).

A video I took this morning - outside temp was about 20 degrees (F). After running a minute or two, the rough idle/stumbling:
http://www.youtube.com/watch?v=3K8gnQ6hJ7c

Mine's a '79, so no CHTS, but I've got a different cold start valve on the way, I'm gonna swap it in & see if that makes a difference.

 

Keep in mind that the mandatory ethanol mix the gas stations sell this time of the year will automatically get you less mpg as well...

 

Quick update, different cold start valve swapped in (as well as fuel pump & fuel damper), and no change in idle issue. Next item to check: air regulator

All the areas I fill up in use RFG, & up to 10% ethanol in all of it year round. Winter formulations change some, but I've been driving around the northeast for 15+ years now, and haven't ever seen a drop that drastic because of it.

Another possibility for my fuel mileage drop - I replaced some fuel line after the pump in the back that was scary bad . . . so worn it's possible it was squirting fuel out whenever I hit a bump.

 

Installed a new coolant temp sensor, but still no improvement. Checked out the air regulator, and not seeing any change in idle when I pinch off the tubes, so I don't think it's working the way it should be. Found someone with a spare, so it's on it's way . . .

 

Hey man did you ever figure what was the problem car is having same problem... Thanks for any input

 

The replacement air regulator helped a little, but now idle speed when warmed up is way too high. And it still doesn't run well at all when warming up. I need to check the ignition timing first, and then probably spend the money for a new air regulator to make sure that's working the way it should.

I just moved & and am buying a business, so I don't have a whole lot of time to work on it . . .

 

I have an 81 turbo and I changed out the O2 sensor about a month ago. Before the changeout, it was running good but mileage was about 15 and I could smell that it was running rich. After the change, my mileage went up to about 17 and the rich smell went away but it idles rough and wants to stall and backfire when cold. Needless to say but I am very interested in a cure.

 

^^^ Welcome to ZDriver!

Check the CHTS (cyl head temp sensor), TPS (throttle position sensor), and AFM (air flow meter) ... sensors AND connections.

Also check the timing.

 

its odd the things people change when the car runs odd. the air regulator is only used during idle, when it is cold, or a/c is on. the cold start valve is only used on cold start up. changing these is only good when idle problems are suspected. starting with checking the values for your temp sensors is the way to go. you actually have to remove them and test them, not just replace parts. its costly and doesnt make sense. use an ohm meter and check them while using boiling water as described in the manual. there are more than one temp sensor, there is acutally some in the t-stat housing. all affecting driveablility.