~ The Mystery Misfire ~

it’s not realistic at this time for me to do it myself. i took it to another mechanic today who is by far the most down to earth an trustworthy so far. he took a lot of free time with me and said he would do the head gasket, timing belt, and water pump, have the hea checked and machined all for $1150 and check for any other problems in the process. he said he was so sure it was the head gasket that a full diagnostic would be a waste of my money. does that price seem fair to you guys for that job? i’ll have to get a loan to do it, but i think i can swing it. he also said he would recommend doing it in spite of the age of the car because he can tell i’ve taken good care of it.

If you are going to have to get a loan just for repairs, you might want to consider getting a bit larger loan and get a vehicle that is in better shape. Especially since your present car will probably start leaving you unable to deliver the pizzas (or to get to any other job you may find) more and more often with its age and mileage. IMHO I wouldn’t put $11 into this car much less even think about $1100.

lol… yeah that’s something to consider. it’s my trusty steed though! we go way back.

If you think you can get another couple of years out of the car it might be worth doing. $1150 is very reasonable for the head gasket plus T belt and water pump. But you better start saving your tip money for a new steed.

Sounds like a good plan. And a fair price.
Sincere best,
TSM

I’m going to go off the wall here and suggest distributor. The crankshaft and camshaft position sensors are located inside the distributor and if the shaft bushing has worn out, it can cause sporadic misfires. The O ring on the distributor is prone to leaking a little oil. I think you will find a heater hose line running right under the distributor, the oil leaks on it, the rubber swells up around the clamp, coolant leaks out there and evaporates on the hot engine so you don’t see it dripping on the ground. It also draws air in at times so the bubbles appear.

Oops, I didn’t realize that there were three pages of posts when I replied, but take a look at the distributor anyway before spending a big chunk of money.

I would also pull the plugs and look at the tips. If there is enough coolant leaking into the combustion chambers to cause a misfire, the tips of the plugs will look like they have been freshly sandblasted. They will be absolutely clean.

Hey guys! New discovery. There is a hole in the exhaust header about a quarter size max. I have a theory that this is causing the secondary o2 sensor to erroneous tell the engine to run rich due to lack of gas fumes detected, and reducing backpressure causing rough starts (flooding?) and low idle misfires. It would also explain why (maybe?) it won’t run rough (even when idling/coasting) as long as the car is moving… maybe something about the heat accumulation when at a stand-still does something to the computers assessment. I’m probably still going to have the head gasket/belt/pump done because it’s an inevitable repair… and it sounds like they’ll replace/repair the header, too. any thoughts?

The O2 sensor doesn’t sense “lack of gas fume,” it senses oxygen. Since exhaust will be blowing out the hole in the header, I doubt any extra oxygen will find its way into the header, so the O2 sensor reading shouldn’t be affected. I may be wrong, but I think you’re grasping at straws.

By the way, how is it that only now you are discovering a quarter-sized hole in the header? It must sound like a machine gun.

The exhaust manifold will undergo vacuum pulses. I had an old Ford Fairmont with fresh air tubes going to the exhaust manifold. These tubes had reed valves to allow air into the manifold. This was a cheap version of the common “air pump” system.

Actually, an exhaust leak ahead of the upstream oxygen sensor WILL cause the sensor to read that excess oxygen

In turn, the PCM will see this as a lean condition, and will command more fuel

Seen it more than a few times

insightful… thanks for your response but I don’t understand what you’re trying to say.

Simply that a leak in the exhaust manifold can introduce air and cause a lean condition to be sensed by the computer, which db4690 corroborated.

The $1100 absolutely will not cover the replacement of an exhaust manifold. If anything it might help with the cost of labor because he has to take the head off anyway. Stop looking for possible other reasons for misfires and easy ways out. Even if you found a simple alternative to fix the rpm issue, you still have an unhealthy engine with a ton of miles on it. You still have a leaky head gasket. You could spend the 1100 and 6 months from now have a bearing go or something else. It WILL start nickel and diming you, and the pizza delivery job is the worst possible job you could have in relation to your vehicle. My advice, take out a loan for 3-4 grand. Buy a car for 2-3 grand. Have a grand reserve for unexpected repairs. Save your money like crazy. Work the delvery job if you must, but get a different one where you dont put wear and tear on your car. I know too well the “its my trusty steed we go way back” feeling as I just had to get rid of mine as well. Youre moving. New place, new job, and why the hell not, new (used) car! A new phase of life.

sometimes it s kinder to put the old horse down rather than watch him suffer. or at least put him out to pasture and let nature take it s course

Yeah, this nag is headed for the glue factory.

For 2-3 there’s plenty of cars out there that are in nearly as bad shape as OP’s car

There’s plenty of shady guys out there that will gladly sell their problem vehicle to somebody else, and won’t mention that they’ve been battling an overheating issue for months/years

They will clear the check engine light caused by P0420, and sell the car before the light comes back on

They’ll gladly forget to mention that it had previously been in a major wreck

They won’t mention that they’ve hooked up some resistors, so that the airbag light stays off, because the airbags are no longer there. Because they’ve been deployed in that previous major wreck.

In my opinion, if OP should get a newer car, he should plan on spending WAY more than 2-3 grand

fender… thanks for the advice, but replacing the exhaust manifold was never the issue… they sai they were going to make sure they knew for absolutely sure that the problem is the headgasket before they start doing surgery… and I trust they’ll let me know if they find anything subsequent that makes the repair not worthwhile… and the hole is in the exhaust header which is a small piece of L-shaped pipe between the manifold an the cat, right… (not the manifold)? I can’t get a new car right now because I don’t have proof of employment or an address. Once I have worked for a little while and I’ve found a place to live, I’ll be in the market for a “new” car. I’m pretty sure I could sell mine for 1100, easy and make the money back for this repair if need be… and there no reason to believe it won’t go to 350k before anything else major based on my experience with it. anyway… I’ll just get it fixed and then see what happens. PS - I found out they have these little dominos smart cars that belong to the store so I’ll have to see how I get myself in one of those… maybe they give that option and then just don’t pay you the normal milage reimbursement. Funny how this has turned into life advice, but thanks for your time and for your input guys.

@‌boober

Please keep us updated

So I got my car back today. The misfire is definitely gone, but I noticed before leaving that the idle was weird and hunting… it would be all the way up to 1500 one minute and all the way down to “0”. If you pump the gas it evens out. Funny it didn’t stall or run rough at such a low idle but I guess that’s good news on the misfire front. No check engine light… and the check engine light comes on when you turn the key like it’s supposed to. The coolant reservoir is way above max but I’m about to check that out myself in a second.

He said that they did the water pump, timing belt, and head gasket. He said cylinder four way full of coolant “evidence” and showed me the old head gasket where there was a gap next to that cylinder at the coolant passage. The gasket wasn’t eaten through completely like I’ve seen online before, just the black coating was silver in that area.

So, the misfire seems to be gone which is great, and these guys definitely are comfortable working on cars an know their stuff… but after looking under the hood I honestly get paranoid and I have no idea what they really did. I was expecting to see a nice shiny new looking cylinder head since supposedly it went to a machine shop. Also the water pump is definitely not new… maybe just a working one they had around. There’s some kind of grey gooey sealant between various engine parts including the head cover and where the coolant exits, whatever gasket that is… I’m assuming that’s a good thing. And a black rubber gasket of some kind that’s lower down… maybe that’s where the head gasket is? You can see the corner of it poking out. Also assuming that’s a good thing.

There’s a broken bolt on the exhaust heat shield and one of the bolts on the timing belt cover was very loose… to the point you couldn’t remove the dipstick. The brake fluid container was not sitting snug in its home and the line leading to it was not clipped in. There’s a sound now that sounds like a crappy loose/broken heat shield under the car at certain speed/rpms… like something thin an metal flapping in the wind… not very obvious/loud but definitely something.

They said this was a “rush” job an that they knew I wanted my car back today (day 3) which I did… but they said I can bring it back tomorrow morning and have breakfast and “shoot the breeze” and they’ll take care of the idle prob (they think it’s a dirty throttle body)… fix the hole in the exhaust (said they just plum forgot to do that), and I’ll mention the bolts and the weird noise, too.

Just giving you guys an update let me know if anything sounds iffy.