I thought I saw a thread here on this problem recently but couldn't find it.

'89 starts OK but runs rough for the first minute or so. Clears up gradually during that time. Feels like one cylinder's not functioning - engine shakes on a very regular cycle.

Some mornings are in the low 30's ºF here now. It's worse when colder, better when starting in warmer afternoon after work. Had no problems several weeks ago when temps were in the 60's.

About a month ago I ran some fuel injector cleaner through (Gumout and Techron, both via the gas tank). Also did a crankcase flush using Gunk engine internals cleaner. This seems to have improved the warm/hot idle which no longer is lumpy as it was before the cleanings.

OK, I'm going to go over all the fuses + fuse contacts. I don't expect they are cylinder-specific though. Seems like one cylinder is out to lunch. Where do you suggest I look first? Propane test around the intake and injectors? I'd have to get a propane torch for that, maybe it's time I got one?
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Ok I am having the exact same problem. Everyone on here has been a huge help, my brick is an 82 245 but it sounds like the same problem. I don't know if your car has a flame trap but if it does check that, change the 02 sensor, and like some of the other guys said change your injector seals. They are only a few bucks and about an hour of work(on my car anyway)to change them just make sure you clean the crap out of the injector ports, I find a 12 gauge shotgun bore brush works really well. After they are all clean use some vasaline and lube the walls, I don't know how the injectors are in your car but I had to change the inners and outers. Check your injectors for leaking, mine do and I am changing them this week you can tell by the smell of raw fuel and obvious wetness at the tip.

If that isn't it it could be your Control Pressure regulator (if it has one) just have a shop test the pressure when its cold and they can tell you. Thats next on my list after the injectors if they don't fix the problem. Hope you can figure it out and if you do let me know, it could be of some help to my problem.

Thanks.

I may get a look at it tomorrow (Sunday). Today was spent with the family. Both adult kids were here for breakfast and they were both nice. I'm counting my blessings.
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Try pulling the plugs after one of it's rough running 'episodes', and checking their condition, wet, dry, different etc. May help to point you in the right direction.
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Gary Gilliam Sumerduck VA,' 94 940 Regina, '86 240GL

If it is your injector seals, Contract when it's cold and leak a bit, you can test this by squirting water at the injectors. It will seal enough to give you a noticeable running condition change.

You don't have to use Starter fluid or propane.
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'75 Jeep CJ5 345Hp ChevyPwrd, two motorcycles, '85 Pickup: The '89 Volvo is the newest vehicle I own. it wasn't Volvos safety , it was Longevity that sold me

Obvious place to start is to check condition of plugs, wires and distributor cap. Then move on to injectors, air leaks etc.
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David Hunter

Yes.
Fresh tuneup two weekends ago. Plugs, cap, rotor. Reinstalled OEM wires that I took out a year ago when I tried something else.

I guess I'll be verifying that tuneup and wires, and then going from there.
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Obvious place to start is to check condition of plugs, wires and distributor cap. Then move on to injectors, air leaks etc.
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David Hunter

How about the ECT sensor? If the sensor is not recording the lower temperature then you will have a lean condition until the engine warms up, rough idle, hesitation, etc. It would not be an issue in warm weather.

Regards,
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Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles, 87 Honda Civic 96K.

OK, I can check the ECT - but it feels like one cylinder is not firing or not getting fuel or is sucking air via a leak. Engine has a very rhythmic shake.

So I'm thinking it's always the same cyl. that has the issue, not a general ailment for all.
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Sven: '89 245 NA, 951 ECU, open-front airbox, E-fan, 205/65-15's, IPD sways, E-Codes, amber front corner reflectors. Wifemobile '89 245 NA stock. 90 244 NA spare, runs.

Can you isolate the cylinder by removing the plug wires one at a time? If it is the same one every time then I would not suspect an electronic problem past a cracked distributor cap. You could run a cold cylinder compression test to see if the same cylinder is down on compression. It sounds like a lean condition since it straightens out when warmed up. A stuck exhaust valve could do the same thing though...

Regards,
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Will Dallas, www.willdallas.us, www.willdallas.org, www.willdallas.com 86 245 DL 222K miles, 93 940 260K miles, 88 765 GLE 152K miles, 87 Honda Civic 96K.