Billy18bm

My car is running very sluggish and hesitates during acceleration

My car is throwing all of these codes:


P0100/P0103-Mass airflow

P0161-H02S (rear of catalytic converter)

P0300 – Random Multiple Misfire

P0400-EGR Valve

P0410-Secondary Air System (AIR PUMP)


Where do you think I should start?
I know its kind of vague, but I don't have a clue due to all of these codes.

rv93

I'd start with the misfire. Thats most likely to affect power. Then see whats up with the EGR. If its recirculating too much, you could be down on power. A bad MAF sensor is never good, but i drove with mine unplugged by accident for a bit, and the car acted funny, but pedal to the metal power was fine. The AIR pump shouldnt affect performance, and the rear O2 sensor just means ur polluting, but thats not the highest priority.

Injuneer

You need to provide basic info about the car - year, model, engine, trans and any major mods. Put that info in a "Signature" so it is always available in your posts.

Post the year and engine, and we can explain the codes.

Billy18bm

Sorry its a 1997 Z28 Camaro

LT1 5.7/Auto it has a K&N cold air and that is it. Im going to update my signature now.

Billy18bm

So i took the MAF off and cleaned it. When i was putting it back on i noticed that the intake elbow has several cracks in it, just past the MAF. Could this cause the MAF codes P0100 and P0103? I have yet to meter the pink and black/white wire on the MAF due to not having a meter but I unplugged it when the car was running and it had absolutely no affect on the motor. I also looked under the opti and didn't notice any burnt plug wires or any damage to the vacuum lines going to the opti.

The car often runs significantly worse when driving in the rain. It also acts worse when the air is very moist when i say sluggish i mean if i am at low rpms it will hesitate and jump very bad. I've ordered a Cap/Rotor,Plugs,Wires, & an ignition coil and am planning a tune up. I am unsure on where I should actually start. I don't have a spare MAF or intake elbow laying around to test it with, but i would absolutely hate to buy an elbow and MAF and that not fix my problem, but if its throwing P0103 and P0100 it seems like the MAF is bad?

any input would be much appreciated. Thanks.

Billy18bm

anyone? please help

eanhl2004

I took my baby to Valvoline instant oil change some years back, I told them not to touch the air filter since I replaced it with K&N, they did...some time later I threw a MAF code, I pulled it all off after finding my air filter laying in the bottom rather than connected... they touched my filter and never put it back on correctly! The MAF was dirty, the whole thing was dirty... I also raced a guy on the street at a light once and my car made a clank/thud and the car hesitated and surged bigtime... later I found that the tranny mount likely broke at that time and since that day I was getting some slight hesitation and surge... I tried to remove the egr valve and when I looked in a mirror at the nuts one of them was slightly stripped like someone had already tried to remove it.... once the mechanic replaced the egr valve the hesitation and surge pretty much disappeared!

I am no mechanic but I would say it doesn't sound good. The cracks could allow dirt into the engine which could cause major engine damage... this is what I've read anyways...

You definately should replace the cracked elbow, and I would get an EGR valve... you can order one online for about $50 and it's EASY to replace provided nobody has stripped it for you! just make sure you use the right size socket and use a mirror to see if you can't see what your doing... I would start there personally... and see what happens...if after that your throwing maf codes still then go from there! There is a way to test your egr valve as well I can't recall for sure though...something like pressing it in at idle and if the car stalls it's fine or not? look it up on here somewhere or google it if you want to test it before buying the part...

any advice Injuneer gives TRUMPS mine... just so you know I am not a mechanic, but I've had similar problems as you and I've been trying to resolve my problems as much as I can on my own!

Injuneer

P0100 is telling you the signal from the MAF is "static".... not changing like it should. The most common cause is loss of 12V on the pink wire. You have to check it. A volt meter costs $15. If you unplugged it and it ran the same, it indicates the PCM is ignoring the MAF sensor and running in speed-density mode, since it can not rely on the signal from the MAF. P0103 tells you the frequency output of the MAF is above 10,700Hz. Again, that's like an open circuit. Either the wiring is bad or the sensor is bad.

The cracks in the elbow between the MAF and the throttle body means that dirty/unfiltered air is bypassing the MAF sensor. Even if the MAF was working correctly, it wouldn't be giving the correct readings, because some of the air is bypassing the sensor and not being measured. Get a new elbow, or at least temporarily duct tape the cracks to prevent dirty air from destroying your rings.

P0161 tells you the heater circuit to the passenger side after-cat O2 sensor is bad. Either a faulty heater in the O2 sensor, or faulty harness wires. Swap the two after-cat O2 sensors and it the code follows the sensor to the driver's side (P0138) its a faulty sensor, and if the code stays at P0161 its faulty harness wiring.

P0400 indicates the PCM diagnostic does not detect EGR flow when it cycles the EGR valve. Could be a faulty valve, faulty vacuum lines or a plugged EGR vacuum solenoid. Or the EGR riser tube from #8 exhaust runner to the back of the intake manifold is cracked, or there is carbon on the pintle of the EGR valve.

P0410 tells you taht when the PCM cycles the AIR pump, and looks at the O2 sensors, it does not see the expected "lean" condition it would expect from the aIR pump air. Could be a faulty pump, burned rubber connectors on the AIR piping or frozen check valves.

Billy18bm

I just changed my spark plugs and my ignition coil and it appears that the problem is fixed. I cleared the codes and so far "2 days" none of the codes have came back up. I think the MAF codes were from a previous incident where I left it disconnected after looking at the air pump. Also where do the two hoses coming out of the air pump go. Should one not be plugged up?

Also I don't know if this is just a temporary fix because my car seemed to run much worse when there was any moisture in the air or if i was driving in the rain. Could a bad coil cause that? I don't think there was anything wrong with the plugs as they all looked fine, but since i had them out i figured i should replace them. I plan on looking at the egr valve tomorrow and trying to clean it out.

One more question. sorry!
There was a small line (looked like some sort of vent) it had a nipple on it and it connected into the intake elbow. I can seem to find that damn thing. What does it go to and is it important, because all of the elbows if found that are aftermarket don't seem to have this hole.

Injuneer

AIR pump piping. The pump takes suction ("inlet hose" on the diagram) from a connection on the main engine air duct, and discharges to the system that pipes the air to the two exhaust manifolds:

Courtesy of Shoebox.

http://shbox.com/1/air_pump_recall.jpg

If the inlet hose is not connected to the air duct, the hole in the air duct is allowing dirty air to enter the engine.

The hose with the blue elbow is the air supply for the Opti vent system, and plugs into the elbow between the MAF sensor and the throttle body. You may have to drill a hole in an aftermarket elbow. Just get the factory 1LE elbow for a 95-97 model. Works as well as the aftermarket, and has the hole.

Again, from Shoebox:

http://shbox.com/1/opti_vacuum_harness.jpg

If you don't have that plugged in, the vacuum is pulling dirty air into the Opti, and the engine has a small/dirty airstream bypassing the MAF sensor.