Miss firing and hot cats

456 started running rough so I changed air filters, from k&n to OEM, and removed both MAF and sprayed them down with maf cleaner, and I removed all spark plugs and gave them a quick bead blast and reinstalled. Then I used deOXit spray on a few electrical connectors around the engine, the air valve, maf, and a few others as I’d read they can be problem areas. But, car runs even worse now. Got a slow down lamp a few times, and the cats seem to be very hot so I think I’m getting misfires and dumping fuel into them. Any ideas where I should look next?

 

Oh I was also getting a hanging idle which does seem to have resolved with my tinkering.

 

Is the slow down lamp only activated by hot cats? Or is there more involved in their function?

 

Sorry, no, only right bank. Flashed a few times, went out, flashed a few more times as I limped it back to the house. I had just gone around the neighborhood for a quick spin.
I looked for the button for reading codes but couldn’t find it behind the Driver side kick panel. This is a 95 so it has obd1 but I have not figured out how to scan it yet. I think I may have a connector contact issue. Most of them looked good but a few had corrosion on the pins, so I might explore that more. Also, I’m wondering about the plugs.
Does the car need to be tuned to run the oem air filters vs the K&N?

 

No, there was no cel either. I had been getting intermittent left bank cel before this, and hanging idle, but those symptoms subsided today. I’m sure the air filters changed the running condition somewhat. Maybe richened it a little due to increased resistance

 

Oh No, that’s odd! Kinda throws that whole philosophy out the window if that’s the case! Lol

 

Those two test ports on top In front? Happen to know what pressure would be normal there?

 

Interesting development: so I messed around with the various plugs again and even checked a few more, sprayed more deOXit in all of them and gave a wiggle. The one that had the worst corrosion was almost clean from the deOXit when I opened it again, so little more spray and plugged everything in again. Reset with a battery off for a few minutes and then Fired it up again and now it purrs like a kitten. Strange. Maybe the MAFs had to burn off for a few cycles to settle in? Or maybe I didn’t get a plug back together all the way? But I didn’t find any loose. Dunno. But now it’s raining so I can’t properly test lol. Will report back if I find out more. Still tryin to figure out how to scan the car.

 

Ah, I bet that’s what it was. Needed more dry time. I usually work the connections wet and then leave them to dry together.

 

yes I think it was a compound error of wet deox connectors and maybe mafs settling in. Thanks for the input. Nice to have support for that panic only a sick Ferrari can induce.

 

I think it was either one or a combo of the following that was all messed with at the same time:
1:Corrosion in connectors on engine
2eOXit spray being wet on said connectors
3:MAF cleaning needing some cycles to settle in

hard to say with confidence which it was but the result of just letting it sit and dry out the deoxit (which also means time for it to continue to do its job) but now it’s running the best it has since buying it. Actually I haven’t really had a chance to test that it’s running better but it sure seems like it just sitting. It’s been winter AF here so she’s been doing some garage time

 

It doesn’t really dry dry, but the carriers flash off and leave an oily residue behind. I’ve been informed that long term this product can attack plastics and rubber so there is a better product out there according to him, and he’s an audiophile nerd who restores old stereo equip.