2000 Coupe running rough

[RLDaily]

How about cruising steady at 50 mph and 1500 rpm and you start to get a little RPM bounce to 1300 and back to 1500....kinda like the fuel is being cut off or a miss?

I just replaced my battery (new red top)

Codes

10PCM P1571 HC - P1689 HC

58SDM B1001 H - U1040 HC

AO LDCM U1064 H

 

[Hib Halverson]

How about cruising steady at 50 mph and 1500 rpm and you start to get a little RPM bounce to 1300 and back to 1500....kinda like the fuel is being cut off or a miss?

I just replaced my battery (new red top)

Codes

10PCM P1571 HC - P1689 HC

58SDM B1001 H - U1040 HC

AO LDCM U1064 H

Understand that diagnosis via Internet is often difficult so take what we say as educated guesses not diagnosis.

The first two faults are current and indicate a problem in the circuits running between the ECM and the EBTCM.

First thing I do is take that new battery out and remove the battery box then inspect the area under the battery for any damage due to the previous battery leaking. Pay particular attention to wires leading to the ECM and the ECM connectors.

Also, there is some evidence you have some other problems with the communications between modules on the Class 2 network.

Lastly, has this car ever had its driver airbag changed?

 

[RLDaily]

Hey sorry about the slam, I'm laid back and as un-PC as you can get so I don't get ruffled

The surging has been bugging me. A highway speed the car runs smooth as silk and I'm getting mileage in the 30's, but at lower in town kind of driving I'm getting this RPM drop like either the fuel is cutting out or there's a miss....and it doesn't feel like a miss

The car is completely stock with about 89K miles, I don't race or run it hard, it's an everyday driver when I'm home. Last fall I went ahead and put new plugs and wires on it...Stock replacement

I understand wrench twisting and this thing isn't any harder to maintain than a helicopter. I'm just stumped


On another not, I frequently run my codes, but is it worth while to get a code reader and if it is what's a good one that won't break the bank? I'd like to be able to read the coil packs and stuff if possible

 

[Hib Halverson]

Hey sorry about the slam, I'm laid back and as un-PC as you can get so I don't get ruffled

The surging has been bugging me. A highway speed the car runs smooth as silk and I'm getting mileage in the 30's, but at lower in town kind of driving I'm getting this RPM drop like either the fuel is cutting out or there's a miss....and it doesn't feel like a miss

The car is completely stock with about 89K miles, I don't race or run it hard, it's an everyday driver when I'm home. Last fall I went ahead and put new plugs and wires on it...Stock replacement

I understand wrench twisting and this thing isn't any harder to maintain than a helicopter. I'm just stumped

I thought my earlier post was pretty clear. To restate:
[FONT=Verdana, Tahoma, Calibri, Geneva, sans-serif]The first two faults are current and indicate a problem in the circuits running between the ECM and the EBTCM and which allow the engine controller and traction control to exchange information.[/FONT]

First thing I do is take that new battery out and remove the battery box then inspect the area under the battery for any damage due to the previous battery leaking. Pay particular attention to wires leading to the ECM and the ECM connectors.

Also, there is some evidence you have some other problems with the communications between modules on the Class 2 network.

I'll add that to solve those fault codes, most likely, you'll need a Factory Service Manual. You can buy them from CAC sponsor, Zip Products.

On another not, I frequently run my codes, but is it worth while to get a code reader and if it is what's a good one that won't break the bank?

The C5's on-board diagnostics are adequate if all you want is the ability to get fault codes. If you want the ability to look at ECM data lists or record data, you need a dedicated device. There are some "code readers" (actually, the proper nomenclature is "scan tester") which can read both the ECM and the EBTCM and are "prosumer" devices with reasonable prices.

I'd like to be able to read the coil packs and stuff if possible

You can't "read" coil packs.

As for other "stuff", as I said above, there are a few prosumer scan testers which will read both the ECM and the EBTCM. Most low cost scanners can only look at the ECM. Scanners which look at all the car's modules are very expensive.

 

[LLC5]

Hey sorry about the slam, I'm laid back and as un-PC as you can get so I don't get ruffled

The surging has been bugging me. A highway speed the car runs smooth as silk and I'm getting mileage in the 30's, but at lower in town kind of driving I'm getting this RPM drop like either the fuel is cutting out or there's a miss....and it doesn't feel like a miss

The car is completely stock with about 89K miles, I don't race or run it hard, it's an everyday driver when I'm home. Last fall I went ahead and put new plugs and wires on it...Stock replacement

I understand wrench twisting and this thing isn't any harder to maintain than a helicopter. I'm just stumped


On another not, I frequently run my codes, but is it worth while to get a code reader and if it is what's a good one that won't break the bank? I'd like to be able to read the coil packs and stuff if possible

How much does the rpm drop (in hundreds please, estimate if you need to), and at what speeds are you traveling, and does it do it at idle? Is it an automatic or a stick?

 

[RLDaily]

How much does the rpm drop (in hundreds please, estimate if you need to), and at what speeds are you traveling, and does it do it at idle? Is it an automatic or a stick?

The engine is about as stock as they come, new plugs and wires last fall and has about 89K miles on it. Throttle body is cleaner than a cats fanny and air is going thru a nice clean K&N filter in the stock air box.

Cruising steady at 50 mph and 1500 rpm and I get a little RPM bounce to 1300 and back to 1500, very much like fuel starvation. It can happen at other speeds as well, but not at highway speeds where the engines is smooth as silk from 70 to 85 or so.

Acceleration is very smooth, no stumbling even during a heavy foot event which is seldom (I'm a retired cop and have nothing to prove in or with my car)

Right now my codes are clear except for the traction and abs stuff. There isn't any corrosion or leakage or any of that from a battery, I maintain this thing as good as or better than I did the aircraft I used to fly on. Under the hood is almost like it was from the dealer

I believe it has the original fuel filter and I plagued with the fuel gage going to zero within 50-75 miles of filling the tanks and it staying that way until it's about halfway down. I'm pretty sure the original owner had used some crappy fuel. The fuel gage doesn't bother me, I'm going into the fuel tanks and changing the sending units out in the Spring anyway...Done deal.

 

[LLC5]

The engine is about as stock as they come, new plugs and wires last fall and has about 89K miles on it. Throttle body is cleaner than a cats fanny and air is going thru a nice clean K&N filter in the stock air box.

Cruising steady at 50 mph and 1500 rpm and I get a little RPM bounce to 1300 and back to 1500, very much like fuel starvation. It can happen at other speeds as well, but not at highway speeds where the engines is smooth as silk from 70 to 85 or so.

Acceleration is very smooth, no stumbling even during a heavy foot event which is seldom (I'm a retired cop and have nothing to prove in or with my car)

Right now my codes are clear except for the traction and abs stuff. There isn't any corrosion or leakage or any of that from a battery, I maintain this thing as good as or better than I did the aircraft I used to fly on. Under the hood is almost like it was from the dealer

I believe it has the original fuel filter and I plagued with the fuel gage going to zero within 50-75 miles of filling the tanks and it staying that way until it's about halfway down. I'm pretty sure the original owner had used some crappy fuel. The fuel gage doesn't bother me, I'm going into the fuel tanks and changing the sending units out in the Spring anyway...Done deal.

If your vehicle is an automatic transmission, the 50 mph and 2-300 drop in rpm is exactly how normal operation of torque converter lock up works. At lower speed (normally 40-55mph) and light engine load conditions, your PCM will lock up the transmission's torque converter for better theoretical mpg. At those speeds and engine loads the PCM "shuffles" between lock up and non lock up because you are right on the bubble between programmed PCM parameters for torque converter lock up conditions to be met. This is all assuming that the vehicle is an automatic, and not a manual.

 

[RLDaily]

Yep, it's an auto like I said with about 89K miles and as far as I know, no hard driving...More prone to do this when cool?

 

[dadaroo]

I'm with LLC5 that probably what you are experiencing is from the torque converter. If it does not do it at lower or higher rpms that sounds like what s happening. If you took a ride with someone with a Tech II and possibly other scanners you could see it the TC is getting a signal from the PCM when this happens.

 

[LLC5]

Yep, it's an auto like I said with about 89K miles and as far as I know, no hard driving...More prone to do this when cool?

You might notice it a little more when cool before the transmission fluid is hot (which takes a little longer than a vehicle with a transmission mounted to the engine), but if lock up parameters are met (cool, warm, hot) lock up will occur.

 

[RLDaily]

It does seem to occur more frequently when the car is cool. I'll pay a bit more attention

 

[Hib Halverson]

(snip)

Right now my codes are clear except for the traction and abs stuff. There isn't any corrosion or leakage or any of that from a battery, I maintain this thing as good as or better than I did the aircraft I used to fly on. Under the hood is almost like it was from the dealer

(snip)

Just to confirm...the DTC P1571 and P1689 reset as current codes after you last cleared codes?

 

[RLDaily]

Yep. I had replaced the battery and didn't clear everything off before driving it around. I need to run the codes again and I will after I derive here for a bit, I just changed the lube in the differential and I'm sloshing it up a bit. (What came out was pretty ugly and smelled like a really dead dinosaur, but no metal chips just the small particles you'll see with machined parts after about 89000 miles)

 

[Hib Halverson]

You're making this difficult.

My questions was: did you clear codes. You said "Yep" but then said you "...didn't clear everything off"

I can't help you if you don't slow down, fully read the posts, then answer concisely.

Again...
Just to confirm...did the DTC P1571 and P1689 reset as current codes after you last cleared codes?

If you didn't clear codes, please, do that now, then road test and let us know if P1571 and P1689 reset as current codes.

 

[RLDaily]

Appreciate the assistance but LLC5 gave me what I needed know, it was as I had suspected but wanted to validate....Oh yeah I have no codes at present!