Gutted cats, 8MPG and codes 44 & 94. Are they related?

[MustangLX-5.0]

I'm still having poor running issues. Still have KOER codes 44 & 94. It surges a little on cold start up, then slowly clears up. When driven, I'm getting no more than 8-10 mpg. I can watch the gas gauge move down in a 10 mile trip. I will lose almost an 8th of a tank in about 12 miles of driving. Btw, I gutted my cats a few years ago because one was rattling bad and another was getting clogged up. Could all of these problems be related in any way? How can I fix them?

 

[stangbang302]

sounds like bad o2 sensors for you gas problem. for the surging, check your tps.

 

[MustangLX-5.0]

For some reason, 44 and 94 suddenly stopped popping up. Now i'm getting 41 and 91 again. It can't seem to make up it's mind. Haven't got around to the TPS yet. I'll have to check that tomorrow.

 

[HISSIN50]

If it was the cats being gutted, you'd have had the bad economy since you gutted them.

What is the actual mileage you're getting? The gauge is not accurate at all.

Surging and lean codes indicate a vacuum leak generally. Also be sure your MAF isn't filthy or otherwise compromised.

Good luck man.

 

[MustangLX-5.0]

Actual mileage, not exactly sure. It was more of a guestimate. judging by how fast the gauge moved down. I usually put about 7-8 gallons in. It'll be at the red line, and after filling, it's about halfway. I'm figuring the mileage varies between 8 - 12 mpg. Seems to always been that way for years. I eveb replaced the O2 sensors a few years ago because I was getting 41 & 91. Thought that fixed it, but then a couple days later, 41 and 91 showed up again I thought the brake booster leaking may've caused it. It was hissing through the pedal. That's been replaced.. along with most other vac lines.. including the long one to the canister. I can't figure out what the cause is. I have a hunce the gutted cats might be doing it. Come to think of it, I believe I started getting 41 and 91 shortly after gutting them out. Cant think of what else would cause it. The surging only started recently, and its only for the first 30 seconds when cold. TPS was replaced along with the O2's back then.. same with the MAF and IAC... and FPS. I went all out and replaced these things back then hoping to cure the codes and running issues. After that, it sat 95% of the time till just recently. MAF has been cleaned. IAC is fine and is totally clean. Didn't even have to mess with it.

 

[HISSIN50]

Gutted cats should not cause the lean codes.

If it only surges for 30 seconds upon start-up, I would not really worry about it too much. Just let it idle or be aware of it while driving it for those 30 seconds.

 

[MustangLX-5.0]

According to the EEC-IV trouble codes pdf I downloaded off of here, 41 & 91 are only EGO related on non-SEFI 5.0. It says Fuel pressure or injectors out of balance for SEFI 5.0. But everyone here seems to say the codes are for the EGO on our 5.0's . Can someone make light of this? Which is correct.. you guys.. or the EEC chart?

 

[HISSIN50]

Can you post up the chart?

The codes can pertain to the HEGOs on EFI stangs.

 

[MustangLX-5.0]

Cant recall, was either you or JR that posted this in another thread.

 

[MustangLX-5.0]

I don't know what happened. I went to pull the salt 10 pin connector. Had a hell of a time, spent 20 minutes trying to disconnect that thing, so I just ended up breaking the plastic tabs and unplugged it. Didnt need to clean it. All pins looked clean with white grease still on all of them. Plugged it back in and started up. For some reason, it started up perfect. Engine didn't surge or po, backfire.. didnt do any of that crap. Ran so smooth. Tested TPS, and came out with 0.99v at idle. Response range was smooth with no choppy breaks in the voltage readings while I pushed on the throttle. After it warmed up, I connected the scanner and had it run a test. NO codes 44, 94 , 41 or 91 this time. But, I did get a code 45 now. Something else to do with the thermactor system. Something about upstream fault. Gotta look again.

The ground strap from the firewall, connector terminal at firewall was removed and cleaned. The other end of it bolts to the back of the block. Same place the HEGO ground is also connected. It's a 2 inch long pice of metal with the O2 wire on one end, and the firewal gnd strap on the other. I don't know how you get that bolt off.. let alone get a good ratchet on it. Aint no friggin clearance. I tried... an tried. Couldn't budge the bolt with a small ratchet, which byw is all that you can fit back there.. Doesn't matter. Since the strap and HEGO gnd are both connected to the same pin, the ground is fine. I tested the resistance between the HEGO ground and the battery ground terminal, 0.0 ohms. And just in case you wanted to know, the DVM is a MAC Tools EM720. So the readings are correct. If anyone has anything to add to this, please drop in. Thanks

 

[MustangLX-5.0]

Wellp... it DID IT AGAIN. Just when I thought it was doing well, it starts surging again. Did this today just after starting it up. This time it went on surging for at least 3 - 5 minutes. And the exhaust smelled rich of fuel. Started hearing some backfires again as well. Gawd, I don't know what the problem is. I sprayed QD Electronic parts cleaner all over every edge of gasket and vacuum hose. Nothing made the idle jump or drop. I checked the salty harness and wiggled the wires.. didn't do anything. When I drove it around today, I got back in my driveway and it was idling at 1000 RPM. Tthen after about a minute, it dropped to 800 RPM. I'm gonna have to check the IAC. There may be some intermittent sticking. But, IAC wouldn't cause surging, just excessive high or low idle.

Geez, I thought it was a bad connection at the salt connector and me unplugging it and back again fixed the issue. Guess not. Haven't checked for codes agai, but I'll bet you 41 & 91 would show up again.

So, I probably don't have a vacuum leak. What else could it be? MAP sensor? Don't have a code for it tho.

 

[HISSIN50]

You don't have a functional MAP circuit (that's a SD reference). It's a BAP on your car and it's not nearly as crucial as a MAP sensor is on a SD car.