The above mentioned Ranger has 160K on it. Plugs and wires have been replaced in the last 30-40K miles.

I have had trouble starting in cold weather (fortunately I live in Phoenix and that is rare). The truck won't start easily and even runs rough for a few minutes but then seems fine. It happens the first cold day of every year. I figured it was the computer adjusting.

Now not only is it difficult to start but it stalls out at higher RPM, like when you are driving on the freeway. It starts easier when it is warm and idles fine. It even accelerates normaly for the most part (not always) up to higher RPM. There does not seem to be an audible miss, though when it stalls there is a little backfire. At this point it is difficult to start all the time and stalls often.

I am pretty sure the problem is ignition and not fuel. I don't get a check engine light. I am wondering about how to test the coil packs and ignition module. I don't really want to start swapping as they are expensive. I looked at the plugs and they seem to have normal wear with some carbon deposits. I did a visual on the plug wires, I will take resistance readings on them tomorrow. Any idea on what the resistance ratio is for these wires?

If you have any suggestions or ideas on testing those components please let me know.

Thanks
Brett

 

Welcome to FTE Sundevil Brett,

I know that the CEL is not lit, pull your computer codes anyway.
________________________________________________
‘90 Ranger XLT: 2.3L, EEC-IV, EFI, DIS, 2wd, Mazda 5sp

 

hummm sounds like the timing is off. to much gas to the engine that would account for the pour starts and backfireing, just in the cold weather the gas has a harder time evapourating and stays in the engine longer. when the engine is hot it litterally slowlly burns off.
could be sometime stupid like water in your tank, methal hydrate in the tank 150ml per tank clean it out.
good luck.

P.S. I'm from canada so i'm use to cold weather starts. -40 c .

 

I had the exact same problem on my '92. I replaced my oxygen sensor and couldn't believe how much better it runs now. It's like a new truck again....just make sure you disconnect the battery when you replace it so the computer can re-learn with the new sensor....good luck.