Who can I trust these days?

[INF3RN0666]

I've heard every single diagnosis to this day about my 2000 impala 3.8L misfire. The car has had this issue for about a year now and has seen about 4-5 different shops. Just today, I paid $550 out of my ass to get a conditional pass on emissions testing. Canadian Tire proves to be the worst shop of them all. Their mechanics think they're geniuses, thinking they're always right... My scanner shows a Cylinder 2 misfire, but they kept saying it was a Random Misfire. So in order to prove them wrong, I let them do what they wanted and change my Plugs and Wires, although I had changed them 3 months ago. The morons were obviously wrong, the car failed again and was issued a Conditional Pass because I spent $550.

The misfire only occurs at idle, and is undetectable above 1200 RPM.
The following have been replaced:
EGR valve
MAF
Plugs (twice)
Wires (twice)
Coils were inspected
Injectors were inspected

One mechanic said it was the lifters and valves and rockers. The next guy said the first mechanic was an idiot, and said it was an electrical problem (but couldn't tell me what it is). Canadian tire insisted it was plugs and wires. The next mechanic said it was the cam shaft.

WHAT DO I DO? I'm sick of this guess work. I already paid enough for useless inspections and useless repairs...

[maxwedge]

So after the 500 did you get your money back for ineffective repairs, Did any body do an injector balance test? Compression test on the suspect cylinder? How were the injectors " inspected". A switch of # 2 injector to another cylinder would check if the misfire moved showing that injector is bad. All this is day to day basic diagnostics. Who recommended or replaced all these parts that were unnecessary? No way I could get away with charging for this work and not fix the car in my shop!!

[INF3RN0666]

Cylinder 2 did pass compression tests and the injector was swapped with one from another cylinder (but the misfire stayed in cylinder 2). Mind you, the EGR and MAF were setting codes, so that's why I agreed to change them. So I don't blame my mechanic for that (he's the one I trust most because he has good experience). My mechanic said the problem was with "lifters and valves" and would be more expensive than swapping the engine with a used one.

I'm pro protecting the environment from emissions. BUT, Ontario emissions laws are the dumbest you've ever seen. Their emissions testing is soooo flawed that a car will pass testing WELL within guidelines. Test the car again at a different time with different humidity and temperature, and the car might fail. A Conditional Pass is where you do repairs for over $450, and you'll pass the e-test regardless. The mechanics at canadian tire are so full of themselves, they disregarded everything I said concerning the misfire because they think they're always right. A $150 diagnostic test there told them to replace the plugs/wires. My issue was, I'm gonna have to pay more than $450 regardless of where I go in order to get a pass. If my mechanic is correct, replacing the wires and plugs, as canadian tire suggested, won't do shit. So I didn't bother arguing with them because there's no other repair they can do for less than $300 that would be emissions related...If I asked for a refund, they would have to find something to fix so that I can pass anyways. Get this, they recommended a fuel injection system vacuum and quoted me at $800. I just about died.

Man, I'm no expert but shouldn't their diagnostic test tell them that replacing the wires wasn't gonna do shit. You just pull out an Ohm meter and test resistance according to specs. Same thing for spark plugs...

If the e-test didn't have an idle emissions reading, my car would have passed. It misfires only during idle... The test showed good results at 2500 RPM.

[beef_bourito]

NEVER GO TO CRAPPY TIRE!!!!

that being said, they're only required to have one licensed mechanic at the store, and he isn't always there. take the car to someone else because canadian tire will always try to make money off of you in any way possible. they tried get me to repair the CV boot, which costs something like $150, but the entire shaft costs about $200. anyways, after they screwed me badly (not just the CV boot, long story and i think you've heard it) i'm never taking my car to them again.

also i take it you're being forced to do an e-test because your car's an even year. mine's a 1992 accord, i got an e-test in august 2006, i went to renew my registration in may and they told me i needed another because it's an even year car.

anyways where abouts are you? if you're around ottawa i can suggest some good shops

[maxwedge]

A leak down test of that cylinder will really tell you if this is a mechanical condition, a worn cam lobe could be suspect here also( very rare), or a leaking intake manifold gasket another possibility.

[INF3RN0666]

Hey beef_burito,

I do live in ottawa, so I would like to hear your recommendations. But get this. My mom's car is a 98 Malibu. I took it in early in the morning to get e-tested. Their machine was being started up for the first test of the day. The car registered a reading of 0 on a few things, and very low PPM for the rest. I know that the malibu has excessive bore clearance, which should make its emissions bad. You can even smell the gas when you first start it up. So I know that the e-testing machine is flawed. Rumors say that cars can pass one time (with a good margin) and fail the next (same day).

What's a leak down test if you don't mind me asking. But I will check the leaking intake gasket.

[beef_bourito]

I live in stittsville so i know a few in this area. there's Mike's garage in richmond if that's not too far. they're pretty good and won't screw you on stuff (worked there for a while so i know they won't screw you) and there's medaglia auto that specialises in honda's so i'm not sure if they'll take yours (i think they will though, they do the odd domestic) but they're very fair. medaglia doesn't like working so they usually try to fix the problem and won't replace anything not worth replacing. if you tell me what area you live in i can ask around about good shops in that area, my current boss knows alot of people so i can probably find you a reputable shop.

[maxwedge]

The cylinder is filled with pressure then the gages read what the pressure in the line is vs what the cyl. pressure is, the difference is the percent of leak, 10% would be acceptable, if the there is leakage past the valves or rings this could be heard in the exh. intake or crankcase. Also if the head gasket is blown to the adjacent cylinder, removing that spark plug would reveal an audible loss of pressure.

[GreyGoose006]

i almost wonder if it could be something like scored cylinder walls creating excessive heat.
if something got eaten by the engine, that might explain it.

you might also have a flat spot on your cam in that cylinder so it isnt letting enough air/fuel in and you are running way lean

[INF3RN0666]

That's what I was told by a different mechanic about the Cam shaft having a worn lobe, but the e-test showed that the mixture is good at high RPM. So I'm starting to wonder about that theory. I'm thinking the cam is fine because the e-test shows a pass at high RPM. I could be wrong.