Misfire no codes only when cold outside
#63
I also noticed that the air intake resonator has a little bit of play when I move it, I don't know if not being on tight without any play will cause a vacuum leak or not. I've checked the tube between the air intake resonator and the MAF and didn't notice any cracks or holes in it.
George
#64
Any unmetered air causes problems because the engine computer does not know about that quantity and computes a bad fuel delivery quantity. As mentioned earlier use the spray test around everything. Brake cleaner or starting fluid works best but its flammable so be careful. Water is not as dramatic and obvious but that works with practice.
George
George
#65
I don't see why not.
#66
I also noticed that the air intake resonator has a little bit of play when I move it, I don't know if not being on tight without any play will cause a vacuum leak or not. I've checked the tube between the air intake resonator and the MAF and didn't notice any cracks or holes in it.
#68
Kenneth here are the pics I promised you of the resistors in the MAF. To this day it boggles my mind that these itty-bitty items can have such a large effect on engine performance. Please handle the MAF very carefully when taking apart and cleaning. Very light touch:
Front side (towards air cleaner)
Rear side (you can see the hotwires (resistors))
MAF taken apart (mine takes a T27 socket bit). Even though there are locating tabs that makes it impossible to put it together wrong. Best practice to keep track of orientation of everything. The reason I take it apart is because I can access the whole element easily. The front side of the resistors is where most of the "baking" happens. I even did someones that was so crusty that I used a screwdriver to scrape off really baked on crustys. Not recommending you do that, I'm just comfortable with it. If you are too concerned to take the MAF apart, just hook your q-tip to reach the front of the wires as shown in one of the pics)...carefully until you get the feel.
I find it easier to remove the MAF housing by taking the whole air inlet off. Especially if the rubber has stuck to the MAF housing. Easier than trying to remove housing while air inlet stays on truck. Just take your time and note what you have to unplug/remove. While you have access clean your throttle body. That's another thing that can really effect engine performance. Pretty stunning how much. Be very careful to not get your fingers caught in throttle body!! I usually put something to prop it open (that won't fall in intake manifold )
While these things can definitely effect performance. I'm not trying to claim this will solve your issue (though as I stated previously, a dirty MAF can have an effect in the cold) it might have some effect, but I'm in agreement with George that a fuel leakdown test is warranted. I used to push that as a first step almost
always. But the fact that you only have the problem on cold mornings and then fine after restart is still curious. BTW, have you done any live data after taking it out for a drive with the restart? If you haven't, that might be something to see to compare. Hope this stuff helps, sorry for getting to you so late.
Front side (towards air cleaner)
Rear side (you can see the hotwires (resistors))
MAF taken apart (mine takes a T27 socket bit). Even though there are locating tabs that makes it impossible to put it together wrong. Best practice to keep track of orientation of everything. The reason I take it apart is because I can access the whole element easily. The front side of the resistors is where most of the "baking" happens. I even did someones that was so crusty that I used a screwdriver to scrape off really baked on crustys. Not recommending you do that, I'm just comfortable with it. If you are too concerned to take the MAF apart, just hook your q-tip to reach the front of the wires as shown in one of the pics)...carefully until you get the feel.
I find it easier to remove the MAF housing by taking the whole air inlet off. Especially if the rubber has stuck to the MAF housing. Easier than trying to remove housing while air inlet stays on truck. Just take your time and note what you have to unplug/remove. While you have access clean your throttle body. That's another thing that can really effect engine performance. Pretty stunning how much. Be very careful to not get your fingers caught in throttle body!! I usually put something to prop it open (that won't fall in intake manifold )
While these things can definitely effect performance. I'm not trying to claim this will solve your issue (though as I stated previously, a dirty MAF can have an effect in the cold) it might have some effect, but I'm in agreement with George that a fuel leakdown test is warranted. I used to push that as a first step almost
always. But the fact that you only have the problem on cold mornings and then fine after restart is still curious. BTW, have you done any live data after taking it out for a drive with the restart? If you haven't, that might be something to see to compare. Hope this stuff helps, sorry for getting to you so late.
#69
Actually after I swapped out the old Duralast cap and rotor for a AC Delco cap and rotor I haven't had a problem with the cold startup misfires. About 3 months ago I put on a new MAF sensor when I was getting a PO 102 code. At the time I also put in a AC Delco air filter because I've read where the Fram and other oiled air filters can contaminate the MAF sensor. About two months ago I also cleaned up the inside of the throttle and the blade. I have a question, is that the gasket you mentioned on the throttle?
#70
Ok, I must have completely missed something. I thought this whole thread was about you having a problem when you first startup and then having to restart before truck runs correct? But yes, that's the "gasket" I made. Wasn't aware of you putting new MAF on truck so basically disregard my whole last post. LOL.
EDIT: I also coat that "gasket" with K&N Air Filter Sealing Grease....I also wear a belt AND suspenders...so take it for what it's worth
EDIT: I also coat that "gasket" with K&N Air Filter Sealing Grease....I also wear a belt AND suspenders...so take it for what it's worth
Last edited by rockp2; 12-18-2022 at 12:20 AM.