With the connectors being loose, check the pins for bends. That’s what usually happens when it doesn’t seat properly or the tabs are broken. These connections are for the fuel injectors and contributing to the misfires.

Theres a vacuum line hidden behind the intake manifold that provides vacuum and is going back to the brake booster. Mechanic missed this possibly?

The pink fluid should be coolant if it’s at the throttle body.

 

Checked the pins, they seem pretty uniform throughout however one tab seems to be broken. All are still wobbly, but I'm going to chalk that up to age and probably replace it. Don't know if it's a direct cause or one of the main causes for the engine's new disastrous condition but I won't rule it out unless I can dig into it for another possible cause.

As far as the vacuum line you've mentioned, it doesn't seem to be loose or disconnected. I wiggled and pulled it, along with other hoses at both bases, and none seem to be installed correctly. I also referred to images, videos and diagrams to make sure every hose was in the correct spot and connected correctly.

Suspicious if the gasket was even installed properly in the first place so I'm going to have to get that checked.

And for the coolant... wondering if the leak has something to do directly with the vacuum leak issue or if the clamp wasn't secured properly. I can't know for sure because the hoses were removed again after the first few failures and left off so I'll have to try and do it myself. I'm more a light casual enthusiastic than a know-what-I'm-doing DIYer, so I may ultimately have to get used to traveling with no car until I can afford to take it back to a mechanic. Lol

 

Why did you "diagnose" that it needed an intake manifold gasket if it was "running perfectly fine"?

 

Op originally had P0171 as part of the original codes posted. Also has evap codes and cat code.

I assume the evap and cat code is still there along with misfires.

 

Try using a zip tie on the loose fuel injector connector to see if it tightens up the connection. Disconnect each one again, only this time you’re looking for any damaged wiring going into the connector body.

Could be a short or when the mechanic cleaned the injectors, they got damaged with the pressurized air. Which will really suck.

 

P0171, P0455, P0441 and P0420

P0171 is almost always the intake manifold gasket, which when faulty will eventually cause the P0420 and can kill the cat. Yes, it's sometimes a fuel injectors problem, but usually it's the intake gasket. This one part is one of the most important things which all Gen 9 Corollas (especially 2003-2005) should have replaced with the updated OE Toyota gasket.

P0441 in my case was a faulty purge valve (it's the one next to the MAF sensor and air filter housing). 2003-2204 and some 2005 use one type of valve, and later years use another.

P0455 is a gross evap leak. Sometimes fixing the P0441 will also fix the P0455 at the same time. It's either a faulty purge valve, or leaky/old evap hoses, gas cap/fuel filler neck corrosion, charcoal canister cracked or has holes from road debris damage. Also evap hoses which are just plain missing or obviously visibly damaged. I can tell you that a 20 year old Corolla pretty much needs to have the evap hoses under the hood replaced. The heat makes the hoses brittle.

P0420 can often be resolved (AFTER the P0171 has been resolved) by rear O2 sensor replacement (use Toyota or genuine Denso only - watch out for fakes). It does require inspecting the catalyst media to make sure it's intact and not plugged up. For me, new sensors resolved the issue for a couple of years. Eventually the cat died because of my previous P0171. The cat mesh media is intact and clean, so I put a spacer on the rear O2 sensor to get rid of the annoying CEL. The only other real solution for me would be to replace the cat, which I have no desire to do.

When I replaced the intake manifold gasket, I followed the instructions in this DIY posted by @hardtopte72 . I took my time and followed the instructions exactly. Zero problems. It's amazing what following directions will do.

DIY 2003-2008 Corolla, Matrix, Pontiac Vibe Intake...

Well I am up here in Virginia for a little while and it's been pretty cold. The past few days my idle has been very low and I knew my original intake gasket had run its course (104k is alright with me). So I headed over to Priority Toyota and spent around 7 bucks and change to get an updated...

www.toyotanation.com

Any mid-level mechanic can do all these repairs, so there's no bad decision in going to a "neighborhood mechanic" (although I don't know what you exactly mean by that term). I'm not a mechanic and even I know how to fix this stuff, so any mechanic from any reputable shop should be able to handle this.

 

Thank you for this valuable information, seriously. I'll look into every point you touched on.

By neighborhood mechanic I mean someone who is just not reputable and works out of their garage. And I just discovered he sprayed carb cleaner and degreaser directly into my engine where the fuel injectors are, so that's more of what I expect from someone who works out of his garage and has questionable knowledge of vehicles and how to fix it and when it's appropriate to put certain chemicals in the engine. I'm begining to think whatever mix of chemicals he sprayed directly into my engine is a prime cause of why things are messed up. I didn't ask anyone to clean out the engine with sprays.

 

EDIT: just discovered he cleaned INSIDE the engine with degreaser and carb cleaner, directly into the intake. Likely the reason my car is in shambles, is my assumption. He sprayed an ENTIRE can into it

This is a problem. A can of degreaser/carb cleaner fluid isn't combustible and could also be a source of your misfires. Take out all the spark plugs and crank the engine and see if it's spitting out fluid which would be the can of carb cleaner. If it's doing that you're in trouble because you will have to get that out of the engine. Running the engine with that in it can hydrolock the engine, then it's game over. If it doesn't spit out any of the liquid you definitely need to change the oil because that means it's drained down into the oil pan.

I agree with the zip tie recommendation for the clips. I'm guessing that the plastic on those clips have gotten so brittle the locking tabs may have broken off. The hoses going to the throttle body are coolant lines and they're leaking coolant. They don't look properly seated and the clamps aren't in the original position. At their age they might be leaking from tearing them when he pried them off. Old hoses don't come off easily sometimes.

Good luck.

 

I wouldn’t start the engine at this point. Everything is fouled now. Would diesel fuel clean up this mess?

 

Just goes to show you that it's not always a good idea to fix stuff that's not broken. On that note, have you talked to a "real" local mechanic to see how much it would be to fix? It sounds too complicated now to fix on your òwn, especially if you are like me and aren't good at working on cars.

 

Fuel injectors are to be checked by OBD scan tool first. It is not definitive that it is the injector or the pump, but big positive fuel trims are indicative of something being clogged or failing, be it at the injector or before. Under no circumstances should they ever be removed with out the OBD check first because you'll never know if the gaskets will seal again, even though the toyota red/orange gaskets are good. Only the updated OEM part is a worthy repair for fuel injectors as well. If one must gamble on the aftermarket, then whatever Denso or Standard Motor Product injector might be ok.

 

After re-reading the OP, I suspect his/her fuel system is partially obstructed at the injectors and/or fuel pump and causing the misfire, not the intake gasket.

Now, these cars seem to be designed to devour spark plugs more rapidly in a lean condition with not much noticeable effect on drive-ability. This is what happened when the Matrix I deal with had devour OEM spark plugs quite severely over 70-80k. Fuel trims were in the 20%, and ultimately ongoing factors were going to cause a replacement of all injectors, and the death of the fuel pump.


The injector connectors have a sort of plastic "cushion" within its center. This material might be some nitrile compound. Unlike viton, which is more non reactive and expensive, nitrile can swell in the presence of brake cleaner or gasoline. Then when squeezed down in this swollen state, it is shoved into the bottom and out of its little "recessed holding area". With a pick or similar, the cushion can be reoriented properly in its recess.

A clear indicator of injector clogging is liquid GOING UP the into the wiring harness.

Injectors can be dealt with in a few ways
1. Dealer OEM new
2. Professional cleaning and refurbishment
3. Aftermarket Denso new
4 Aftermarket Standard Motor Product new.
5. Junkyard Match from some totaled vehicle in same generation.
Never use Ebay Injectors. The rubber O-ring is garbage and not the properly material to handle gasoline. I fell the temptation and got gas flowing down into the intake out of control after a few months, creating no start when engine is hot.

The hoses might be oil-hardened. The leaking hoses are leaking coolant from as the throttle body needs the heat.

 

any old suspect vacuum hoses, replace

 

I have an 05 Corolla s with 295,000 mi on it, still runs like a champ and I'm the only one who works on it
that being said in 2022 I learned a valuable lesson about listening to other people about how much oil goes in my car like what O'Reilly's computers tells them. . .

LMAO never again!!
this humbled me, made me feel so dumb. that being said, I don't know if you're familiar with what goes on when you overfill your car with oil but let me tell you, I learned all the internal details of my car in the week that followed this. including the manifold, the intake, and the throttle body. and I'm a professional I tell you at getting oil out of all of those parts successfully and completely. . .

now the manifold gasket that I got, brand new since I was going to have it off and cleaning it (I used degreaser and carb cleaner in it, it is combustible, it dries really quick with no residue, and it's really good for cleaning those kinds of parts.) and the brand new gasket that they sent me that was "supposed" to be approved, and certified to be just like the one that's replacing. it was not. . . it was too rounded, and it was not as thick as the original at all. I could tell if I put that back in there it wasn't filling the groove created for it but about halfway. I even checked it and it was the one, I ordered the right one.

I ended up cleaning the one I had because it wasn't real dry rotted and i put it back in because I knew the other one wasn't going to seal off and keep air from, you know seeping through, and it's worked fine for me ever since. maybe that will help Idk, also I sent these pictures so you could verify that each hose is going where it's supposed to go you know what I'm saying because there's a lot of hoses that come off that throttle body, but it would be really hard to mess those up, I mean they're bent a particular way, and they only reach where they're supposed to go, as long as you're not forcing it on another spot it should just slide up where it's supposed to be on those hoses. also not too hard to take that throttle body off and you know check it yourself those Little motors are not too hard to work on yourself at all.

 

All looks good from what I can see. It is the hoses that are buried deep seem to be the issue. Is it running like a champ again? If so, all the hoses are probably where they should be................and remember 4.4L of oil!!

 

This all is screaming vacuum hose, the emissions sticker is the roadmap, they should have been replaced, I bet some are dried out and broken. Intake hose hose dried out and cracked. Injector orings leaking vacuum. Cleaning things with carb cleaner is SOP. With car idling spray carb cleaner or even WD40 where the injectors mount into the intake, see if things smooth out. HTH. me-Long time ASE mechanic.