starsong45

First I want to start with the issue that was at hand 2 months ago, since it may tie into the current issue some how. Out of no where my car started over heating, no leaks were detected, engine coolant was filled and the reserve was full. We little by little replaced sensors and relays and thermostat/gasket, and fan..the car still overheated. It didn't matter if the heat was on or if it was off. Then out of nowhere..it stopped overheating. It wasn't driveable for 7 days, because within 10 minutes (from a cold engine) it was blasting in the red zone over heating. I finally caved and took it to a garage, they found nothing wrong with my car 😤. After that it ran perfect. Until now, now it's misfiring on start up. It wouldn't stay running for 4 days in a row, I'd turn it on and it would shake and shut right back off. I pulled my ignition coils off and took them in to be tested, they were good. I finally caved again and had a mechanic come look at it, and of course my car started right up and ran perfect 😤 so again they can't diagnose a problem if they don't see or hear anything wrong with it. This time however a check engine light came on, so I took it to have it hooked up to diagnostic tested. It came back that all 4 cylinders are misfiring, nothing showed up as to why my car wouldn't start for those 4 days. The guy at the place I had it diagnosed said I just needed a tune up with new plugs and wires. Now today, a week after my car has been running excellent (minus startup, it was a little rough idling, and service engine light would flash a few times then disappear, then the car would be excellent) it won't stay running. It starts up, idles really rough and stalls out. I tried giving it some gas to see if that would help, but it acts as if I'm not even pushing the accelerator. Where do I need to look to fix my baby? Because I'm being pulled in oh it's this oh it's that and I don't have 1000s of dollars to play hit or miss if I can help it. Thanks in advance for anyone that can assist me!

Colin42

year, make, model?
transmission type? mileage?
what are the actual code numbers? Pxxxx?
Any parts store will scan your car for free and give you the code numbers or buy a scanner for $20

starsong45

2005 Honda Civic EX, manual transmission 172,000 miles, codes: P0301 cylinder 1 misfire detected, P0302 cylinder 2 misfire detected, P0304 cylinder 4 misfire detected, P2646 VTEC oil pressure switch circuit malfunction, P0134 HO2S S1 circuit high voltage/no activity, P0300 multiple misfire detected

Wankenstein

Possible leaking intake manifold gasket or other vacuum leak.

Do a smoke test on it to rule out intake leak.

GolNat

iTrader: (7)

Head gasket probably went. Common 7th gen issue.

Did this person do a tune up or just suggest it? What do the plugs look like?

starsong45

I changed my plugs, wires and ignition coils, the new o2 sensor should be here today to put in, and I changed the oil and filter. I put some fuel injector cleaner in late yesterday and then it started right up, so I took it to have diagnosed to see if it was still misfiring and this time all the same things popped up as well as saying my EGR valve is the underlying issue. If my head gasket was blown what other symptoms should I look for? My oil looked normal, it hasn't overheated since 2 months ago and it's normally driven daily, highway travel. The spark plugs that came out were normal appearance according to the various charts I've looked at

Colin42

Read:

https://www.civicforums.com/forums/3...reference.html

Wankenstein

Try an ECU reset (idle learn) to clear codes by:
1) Disconnecting the negative cable terminal from (negative) battery post.
2) Turn on headlights and pump brake pedal a few times to discharge residual
3) Turn of all electronics: radio, headlights, A/C, etc..
4) Reconnect negative terminal to battery
5) Start and idle engine (all electronics still off) until radiator fans engages twice (roughly 15-20 minutes). Idle only..do not accelerate engine
6) Shut engine off
7) Restart engine and note any codes ( if any).

Hopefully, no CEL codes will return. However, some may come on right away and some may take a few days or more to return.

You will need to enter a radio code and reprogram if you have stock radio.

EGR = P0401 code. Related read: https://honda-tech.com/forums/honda-...-code-2580610/

starsong45

I will give that a try thank you and thank you everyone for your advice