I've got a miss, hopefully someone can help

[black2002ls]

Not sure if this would be the right forum, I've talked to everyone I know and the local stealership wants near $100 to hook it up. This is a 2003 S-10 with a 2.2l 4 cyl engine

Ok. Have the fuel pump and filter changed cause the pump went out. New pump, new sending unit, new filter, new SES light?!? Take it back to the shop, its running just fine, no apparent fuel leakage, or bad gas mileage. They pull the code small fuel system evap leak. No big deal doesn't seem to be causing any issues and I can't afford to be without my truck at the time. This was mid December. Well early this year I pick up a miss. I managed to live with it. Changed plugs and wires, no help. O'Reilly's wires, and NGK platinum plugs. The miss continues to get worse. Sometimes seeming as if it gets worse the hotter it gets outside or the longer the truck has been running that day, also, If I am running the A/C and there is an increased load on the engine it will miss. Well it comes and goes no real consistency. So I live with it. Well I finally had the cash to pick up a coil. Engine code read miss on cylinder #3. So I replace the 2/3 coil. Crank it up, runs fine, fresh from an oil change life should be great. Take it down the road, I get a little bit of the miss, then its gone, truck is running great (not to mention when I lit it off right after putting the coil on it started better than it had in the 1 1/2 years I've had the thing.). In town I hit the A/C give it some load to try and make it miss. As the day wears on the miss begins to come back. !#$!#%#@$ it. I make a trip to pay the house payment, on the way back it didn't stop missing, no one in miles to help me, and no tools on hand. Get it back home, pull the tire, The bolt for the coil toward the back of the block had come loose. So I crank it down, put it all back together take it for a spin, seemed ok at first. Then the miss starts to come back. Not constant, back to the way it was before the coil was changed.

[Scotch]

You realize, of course, you've been able to 'fix' this several times. The coil packs should be secured and double-checked.

MSD does make hotter coil packs for this application if you want to upgrade.

I also had a 2.2 S-10, and the engine seemed to have an inherent slight miss. It drove fine, so I never worried about it much.

Then I upgraded a few things- K&N FIPK, Magnaflow exhaust, and the MSD coil packs & wires. I also added Bosch plugs.

The miss went away and never came back. The truck made a bit more power, and sounded better with the Magnaflow muffler. The biggest change was in fuel mileage- it went up measurably to around 30 mpg on the freeway.

Otherwise, the truck was okay. I had to change out the Dexcool and flush everything after I got corrosion in all the freeze plugs, though. Keep an eye on that. Regular green coolant is the fix, and it works fine.

The 2.2 was a decent engine. Not the kind of power I'm used to, but better mileage than anything I've ever owned.

Step up the ignition parts, and make sure they are installed securely. That should cure the problem.

~SP~

[black2002ls]

Thanks for the reply. I noticed the little burp from time to time, both on this truck and on my 02. I heard bad things about the MSD units a lot of people having them go out in a year or less. I replaced the plugs again today on my lunch hour, well all but number one, it will have to be done sunday when I'm off. I went to Delco plugs. I wanted copper but all I could get were platinums. I left the battery unplugged for a couple hours to clear the computer (unhooked it when I got to work, re-connected when I went to lunch). Changed plugs ran it around a bit to get it warm, hit the a/c trying to make it miss...all is good in s-10 land. Went to pick up a friend, and the miss came back. It missed solid for near 5 miles. Would go away and the SES light would go out when I hit a stop sign, then all of a sudden it was gone. Came back a little later in the night. Its really hard to pin this down. I've had some people say they had a similar problem and it was caused by a failing catalytic converter. I may just have to live with it for a while. I can't afford a big repair bill right now to pay someone to pinpoint the issue. I'll have the local auto zone run the code and see if it is still the #3 cylinder missing when I get a chance.

Thanks for the input!