Loses Power while cruising.

[tom04841]

This has been an intermitant problem for the past few weeks. It will surface then go away. Then come back again.

What it does is, when i go to take off....light throttle, it will buck, and have no power. If i rev it up, it will go fine. Then while crusing, it will act like i'm not even pressing on the gas pedal at times.

I have an SAFC....been on there for a while, so thats not the problem. Didn't do the O2 mod till yesterday so i could monitor the O2 voltage since my logger is busted. Here's the scoop. When it loses power during cruising, my O2 voltage drops to .000 volts...like its decelerating. Then all of a suffen come out of it and start cycling again like normal.

I am purely using the O2 voltage as a diagnostic tool.

Here is what i have checked/ replaced

1. New spark plugs (7's gapped to .28)

2. Tested for boost leaks (even though its not a boost leak since it does it when i'm not into the boost)

3. New Accel 8mm wires 3 months ago

4. New fule pump 3 months ago (stock replacement)

I am clueless to what this can be since it is intermitant...someone please shed some light!!!!

 

[andymoraitis]

Based on what you're telling us, and the fact that your front O2 voltage is dropping to zero, it sounds like the front O2 sensor needs to be replaced. If the rear unit goes, it only throws a CEL, but if the front unit stops cycling properly, it will throw the car into limp mode. Has your fuel mileage been suffering as well (more than usual)? Another possibility is that your coolant temp sensors are shot. This will basically keep the motor from coming up to operating temp and also cause some of the symptoms you're experiencing. If temps on the gauge are solid (middle) then I would go back to the O2.

The best way to look into all of this would be to use the logger to scan for check engine codes or have the car scanned at a local AutoZone and see if something comes up rather than replacing random parts in the hope that it'll fix your problem. It could be ignition or fuel related problems (fuel filter) that aren't apparent to us since we're not driving the car.

Let us know what you find,

Andy

 

[tom04841]

It is 91...ODB1= 1 O2 sensor. The O2 won't cause the car to buck like a horse. I ran my 90 Eclipse with no 02 and thats all it did. All it will do is make it run pig rich. And gas mileage will suffer. It is not an O2 related problem, but thanks you for your reply.

 

[andymoraitis]

Tom,

Whoops! My bad on the O2. I would still have the codes pulled though. No sense in guessing.

Keep us posted,

Andy

 

[S_Ranger]

Have you checked all hoses? My car would buck from the start and I was wondering, what the heck? Checked the uicp (Upper Intercooler Piping) and it was pretty much off the throttle body and licp. So check for leaks. It's the small things that kill ya.

 

[tom04841]

No leaks, no codes. WTF Oh yeah, new TPS...adjusted properly, and it idle PERFECT.

It does it in neutral too. I slowly give it gas in neutral and the rpms will bounce until after roughly 2500 RPM's. If i keep it above that, it seems to be ok.

I am going to try some new wires.

 

[tom04841]

Well, i just wasted $45 on new wires......it isn't the problem.

 

[ddavisaf]

*Check the capacitors on your ECU.
*If your plugs are older than 4 months check and make sure they're not fouled. If you *didn't gap them when you put them in, make sure the gap is .028".
*Check the connector for the O2 and make sure it's not loose, or corroded.
*Make sure you don't have an exhaust leak pre O2 sensor.
Post back

 

[tom04841]

ECU caps have been replaced. They weren't leaking, did it as a preventitive measure.

Plugs are a week old....gapped to .28

O2 connector good and tight...checked for corrosion...none.

No exhaust leaks at all.

Coil packs ckeck out fine.

No vaccuum or boost leaks.

I did find that the vacuum lines to the EGR are disconnected and plugged. Didn't feel like messing with hooking it back up according to the vacuum diagram. This shouldn't make a difference with the lines disconnected but plugged, will it? Since alot of people get rid of all the vacuum lines anyway....except the one to the FPR.

 

[tom04841]

From the recommendation from the dealer service dept, i unplugged the MAS. Ran rich, but problem wasn't there. Then he said to plug it back in and put a towel around my K&N filter to restrict flow a little....problem gone. Took towel off, started doing it again, but went away after a minute.

He said that the K&N could be allowing too much airflow and a denser charge in causing a lean condition at part throttle.

Make sense i guess, so i was going to richen my afc up a bit at the 1000 RPM point, but the problem vanished for now.

Anyone hear of this? It has gotten COLD out since this started happening.

I am totally confused.