Help, power loss, missing!

[thecause17]

I have a '97 SOHC, drove it to work today with no problems as usual. It always runs very well. But when left work today it felt like somebody took like 50 horsepower away, there is no low end power, and it misses a little at idle. There is no check engine light of codes of any kind. I guess a good comparision would be what it would feel like if you tried to pull out in third gear, it just doesnt' want to go, the engine almost sounds like it's under a load even at ligher throttle now.

As far as I know the timing chain tensioners were replaces shortly after I purchased it at 75k miles, when I took it back to the dealer I bought it from when it started making the noise. I also recently replaced the intake gaskets about 2k miles ago.

Can anybody help me fast, it was like night and day it was fine when I pulled into work thismorning, and then whenI left today it feels like a totally different vehicle.

 

[snoborder42]

I could be a lot of things, I might be leaning towards a fuel delivery problem. It might be the oxygen sensors. My 92 seemed to be underpowered and i changed the o2 sensor and it helped.
Have you changed the fuel filter?
Do you hear the fuel pump right before you start the engine?

 

[jimbo74]

if its running, the fuel pump works.... if the pump dies, you will not have a running vehicle but a no start condition

 

[thecause17]

It starts find and doesn't act like it actually wants to stall, it doesn't shut off at all...I dunno where to start. I checked all the plug wires, thought maybe one came off or something, no luck, looked over vac lines, nothing. Engine temp is normal, good oil pressure, nothing out of the ordinary other than the actual power loss and miss itself, no smoke, nothing.

 

[drstein]

I have a 1994 that's been doing that too.. rough idle, loss of power, and the gas mileage went to crap. Got an OBD-1 code reader and everything points to a failing o2 sensor.. so that's what I'm going to try replacing first.

~$50 part, just gotta see if I can replace it myself..

 

[thecause17]

That much of a power loss though? I've had O2 sensors go in the past, but it seriously feels like I'm running on like 3 cylinders. I had one go bad when I first got it, underwarranty...I got a check engine light and that was it, didn't run any different.

 

[ashleyroachclip]

I am having the same kind of problem with my 94 Ranger , as well as my 91 Explorer...I ran codes on both ....and they pass ...both get 111 in both test modes ....But I have ben told that I should be running platinum plugs , I am using the Motorcraft 745....I also have noticed about an 80 mile difference per tank full..when the engine is just off Idle ...there is no miss apparent....only at an Idle , and I can feel an occasional glitch @ crusing speeds ....I've gone from 300 miles to the tank to 220....that is a big drop ...Maf is clean , everything seems good ...any clues?

 

[snoborder42]

My 92 explorer had this problem. I was noticing a loss of power and rough idle. Every now and then it would sputter on the highway. I got a check engine light once and then it nearly died while going 70 on the freeway. I changed the o2 sensor and now the idle is perfectly smooth and it gained back a lot of power. I was also told that sometimes the o2 sensors will become plugged with carbon and they will still work but not as well as they should and if this happens the check engine light will not come on.

 

[thecause17]

The problem is, with 4 O2 sensors and no code to direct to which one, it'd be hard to pinpoint which sensor, and I'm not just gonna hang parts on it to see what will work. Tonight I'm gonna change the plugs and see if that helps.

One thing that has been bothering me today is that the brakes seem weak. I'm not sure if it's a related issue or not, but if it is, that would point toward a vac leak to me, and I've looked over everything as best as I could and found nothing.

 

[TSTONE]

Sounds like a bad cat to me, i'd try undoing the cat from the ypipe to relieve pressure then drive it, if the power comes back then you have your answer

 

[thecause17]

I know it's not a cat...it still has top end power, and if anywhere was limited by a bad cat it would be top end, where exhaust flow is highest...


I do have an update though...I just got done changing plugs...I'm glad I did though, because somwhere along the line, the previous owner had them done, but only 5 were change, and the right rear most plug was an original motorcraft plug (105k miles) and it looked pretty bad. However, it doesn't run any different with the new plugs in it.

I was messing around, and I unplugged the MAF....and there was no change in the way it ran? No CEL came on or anything, acted as if I had done nothing. Is this normal? I thought this was kind of odd myself. Any input?

 

[thecause17]

Cleaned both the iac and MAF today, with no change. Anyone? Please help, this is horrible how it's running. Tomorrow I'm going to change the plug wires also.

 

[thecause17]

New wires, and fuel filter, no change....

Anyone have anymore ideas, I'm running out here, and starting to get worried this is something really serious.

 

[Billy177]

reset the computer and see if the power comes back

 

[l1tech]

Do a fuel pressure test and an exhaust backpressure test...a plugged cat will be more evident at lower speeds when you are trying to accelerate then at higher speeds

 

[thecause17]

How do you do a "backpressure" test?

 

[l1tech]

If you don't have an exhaust backpressure tester just disconnect the cats and run it, depending on the tester you either put it in place of one of the oxygen sensors or drill a 1/8 inch hole and insert the tester there, then you drive it and monitor the pressure in the exhaust, anything over 5 to 7 psi is a sign of blockage, although you probably won't feel a power difference until it gets over 10 psi

 

[Creager]

what about the coil pack/distributer...

 

[thecause17]

My gas milage also dropped to 11.5mpg...

 

[thecause17]

Another update...I tried a new coil today, no change at all...I called Ford, they said not to bother with a diagnostic test if it's not throwing a cel...they said it would be waste of $82. I'm really running out of ideas, and am staring at the list of OBD-II codes, and pretty much any fault will result in some kind of code...even if the timing was off, it should be causing a rish/lean condition on one bank, and there's even codes for things like that, misfire codes for each cylinder, cat flow codes, egr flow codes.... I dont get it, I'm running out of ideas, and this is killing me. I'm changing the pcv valve tonight cause it's cheap and worth a shot, but I honestly don't look for it to get me anywhere.

Anybody, anything, pwease, I'm getting desperate.