You need to hook it up to a scanner and check out the values for the MAF and O2 sensor when it bogs down.

 

Does it bog down if you rev it in neutral?
How does it behave if you keep your foot on the gas?
A video of this happening would be very helpful.

 

I'll give that a try and try and get some video.

At key on before the engine starts all lights on the dash are supposed to light up. So you can know if the check engine light bulb is good.

Yeah, it comes on i think. Thing is when I swapped the MAS or MAF (not sure the correct abv.) i forgot to pull the negative power cable to reset the ECU. I might try that just to fully rule out the sensor.

 

Are the wires leading to the MAF damaged? Is it possible the bulb for the CEL no longer functions? Does it get out of limp mode if you disconnect the battery for a while?

 

All good ideas from the group

I'd test to see if the fuel pressure is keeping up.

 

I disconnected the negative battery cable for an hour to get it out of limp mode. Took it for a drive and it hit 3,300 before it started bogging down. I only tried flooring it once. Before it consistantly bogged down at just above 3000.

No visible damage to the MAS wires.

Ill try reving it in neutral tomorrow. Also scan it to see if the CEL light is burned out. I hope it is...

 

Try to get some codes. Mine would bog down due to O2 or MAF. You could try cleaning the MAF with MAF Cleaner or Electrical Cleaner. I've found spiderwebs and dead flies on mine and it has saved me some dough.

 

At key on before the engine starts all lights on the dash are supposed to light up. So you can know if the check engine light bulb is good.

 

MAF I believe is the only correct abbreviation. At least by my experience.

I shouldn't have assumed I knew what you meant by MAS, I could have created confusion.

MAF
Mass Air Flow Sensor

So I can see where you get the S.

 

Personally,

With live data, I'd be looking for any PID or data display about your car that went way different as you came up to 3k RPM.

I've seen it be the MAF, but it could be other things.

As you push on the gas pedal the MAF should slowly ready more and more air, or quickly for that matter.

If for example your front O2 sensor, or is it an Air/Fuel ratio sensor that year? If it suddenly goes lean above 3k RPM then it's probably a fuel pump.

O2 sensors show less than .45 volts to be lean and AF's show it by being less than 14.7 parts of air to fuel. Actually, lol, I was watching the data display on the 9th generation yesterday, a 2005, so I'm sure it is an AF.

 

Well i swapped in a MAF i know is good, reset the ECU by pulling the neg. batt. cable for 10mins. The check engine light came on momentarily during start up (as usual), then turned off. I let it run for 45secs then brought the RPM's up to 4,500. Everything seemed normal. I'm guessing it's getting enough fuel and spark, as everything seemed smooth...

So then i went to drive it. Drove 4 blocks before i gave it a bunch of gas to get the RPM's up, and it wouldn't let me much past 3,000 before bogging down. I'm going to try topping off the battery's charge as one last ditch effort to figure this problem out before i bring it in. Maybe it's a low voltage issue? I wish i had a highend scan tool to figure this out but i don't. Anyone here in Minnesota with one want to make some bucks? haha

 

I let it run for 45secs then brought the RPM's up to 4,500. Everything seemed normal. I'm guessing it's getting enough fuel and spark, as everything seemed smooth...

So then i went to drive it. Drove 4 blocks before i gave it a bunch of gas to get the RPM's up, and it wouldn't let me much past 3,000 before bogging down.

This suggests to me the fuel pump can't keep up with demand.
Bad pump or clogged filter.
Revving to 4500 in neutral/park uses very little gas compared to driving.
I would set up a fuel pressure gauge to monitor while driving.

 

Drive to an Autozone to get codes and go from there. They give out free diagnostics. It could be an O2 sensor, it could be fuel or spark, it could be electrical. The codes will greatly help.

 

With no check engine light there is no code. Need something that reads sensor voltage, and someone who has knowledge on how to read these voltages for clues to what is happening. I hate paying to have it serviced (I do 98% of my own mechanic work) but a professional technician is the only way I see this issue being resolved.

 

Let us know the follow up if you decide to take it to a mechanic. Curious if it was a sensor or fuel issue.

 

Are any of your vacuum, PCV, brake booster, or VSV evap hoses off or reversed? Make sure you didn't miss the elusive brake booster hose on rear of intake manifold inlet.

 

Really good advice, when we changed my clutch we switched a couple vacuum hoses by mistake and it ran like crap. There's a couple that are real easy to mix up.

 

Had to give in and bring it to a shop... So after a myriad of tests, a technician is pretty well convinced that the ECM is bad.

Question to the experts here, since the service manager didn't know off hand, would a used ECM need to be re-flashed once installed? Looking to source from the junkyard and DYI in my own garage. Or should I install it in the dealerships parking lot just in case it needs a re-flash?

 

I don't think it would need to be reflashed. I could be wrong though.

 

Looks like there was a ECM recall but not sure if mine falls under the recall. I'll have to look into it.

http://media.fixed-ops.com/Toy_Campaigns/A1J-interim.pdf

 

Guys, the fuel pressure was checked. Everything was checked....

The only thing we can think of is the ECM is bad - which is a known issue on these cars. The ECM part number wasn't part of the safety recall but it falls within the "bad" years. So i'm going to swap a junk yard one in and hope that fixes the issue.

 

This set of years does need to be flashed/programmed by the dealer for it to work properly.

I should know, my buddy had a the wrong PCM and thankfully it fell under a factory recall (but not until after we bought a junkyard one). I hate shipping stuff back to eBay! The seller is being cool, but still. :/ The dealer should have realized that before we went off and bought parts.

You need to ask the dealer what is the right PCM for your VIN. It was difficult, but we did manage to buy one with the right number on eBay for about $90.

Through the dealer with programming, it would have been over $900.

 

They're pretty easy to get to if you have torx bits. Just squeeze the glove box and it basically falls off. Unbolt it all, clean the connections with electrical cleaner, reinstall.

Couldn't hurt to try.

But if you really checked every sensor for it being valid, then it really should be the PCM. Wiring to the PCM would have been caught by a code calling a part bad, that really would be wiring, so if the parts are good, and PCM isn't reporting an issue to show it's parts or wiring.

Sorry for the above run on sentence, had a lot of if's I tried to stack in there. Hope it makes sense!

Sigh...it's a guess, but it could be correct.

 

VIN has to be programmed to ECU.

 

Throwing parts at a car is generally the most expensive way to fix it.

In post #2, I told you what you need to do. What "myriad of tests" did the technician do? Bogging is generally one of very few problems. Also the problems you are having are not at all common.

If we could see some live data graphs, we might have been able to diagnose it already. Before replacing the ECM, it would help to know what the car thinks is going on.

 

I try to be gentle and supportive. I hope I don't offend.



I agree. I'm quick to help others. I like you, like to share my knowledge.

When it looks like the best advice is ignored, I tend to clam up. I tend to leave a tab open when it needs a response until I can respond. This tab, if memory serves took days to get back to because the most definitive tests either weren't done or weren't reported in convincing detail. I realize live data is a serious skill and requires equipment that not everyone has, but basic gear has become so inexpensive that this data has really become accessible to everyone.