TPS..or..Overdrive..or..Fuel Pump??

[crashtestdummy]

Okay so I have search over the forum trying to see if somone has already posted this question and haven't quite found a similar post.

I have a 97 Ranger 2.3L 4cyl automatic trans w/overdrive. Recently between the speeds of 30-40 mph while holding the throttle steady the truck feels like it is slightly losing power then gains it right back even though I haven't pressed on throttle. I have examined the throttle cable and all connections to the throttle body they are all very solid and tight so the problem isn't there. What is odd is when I am at freeway speed put the cruise control on at 65mph I don't feel this loss and gain of power???... Maybe it is still happening but at that speed it so so suttle I am not feeling it as compared to a slower speed of 30mph. I experience this issue even with the overdrive On or Off.

Seems like if it was the fuel pump that is dying, I would not just feel it at slower speeds but at any point in the powerband. Also there is NO check engine light and NO codes have been thrown out from the computer?

Alright Ranger Guru's let's see what you think?

 

[Earl43P]

Welcome to The Ranger Station.

I'd suspect the EGR DPFE. Does it feel like "trailer hitching", kind of a quick die/surge?

You can pull the vacuum connection off of the EGR valve and drive it like that for a day or so to see if that affects it (the computer will disable EGR and set a CEL while it is disconnected). If it stops that behavior, I'd bet on a bad DPFE.

It can take quite a while for the computer to set a CEL for a bad DPFE, but it's a common problem with Fords.

 

[crashtestdummy]

Thanks for the quick reply. I will disconnect tonight and drive the rest of the week to see if it solves the issue. Let you know the outcome this weekend.

 

[kman]

could be ur fuel filter is getting gummed up

 

[crashtestdummy]

Kmon, I thought of that one and since it was easy to replace I already have put a brand new fuel filter and it didn't solve the issue.

 

[Bryan22]

when you feel the loss of power does it seem like the engine idles up, even when your foot is steady on the pedal?

 

[crashtestdummy]

The loss of power is very small. I don't have a tach on this truck but if I did I would guess the loss is no more than 100rpm, so I would say no to your question, it doesn't drop anywhere close to idle level.

 

[bcost882]

sounds like the A/C compressor. when i was in NV when i had heat on it would kick on the compressor at intervals and i would feel it....maybe my truck has a prblem but it seems the exact same thing i had. I would drive around base and feel it at 25-35mph but at highway 60-70mph it wouldnt feel the same. you can prolly clean the MAF and throttle body but this is my idea wuts happnin

 

[crashtestdummy]

You make a good point about the AC compressor only problem I don't have AC in this truck

 

[bcost882]

You make a good point about the AC compressor only problem I don't have AC in this truck

right on.....on with the diagnosing haha

 

[crashtestdummy]

Okay it appears it might be the DPFE sensor. So i got a replacement and just installed it last night. I am going to drive on this week and see if this solves the issue..

 

[crashtestdummy]

So after driving with the new sensor installed something is not right. My first guess was that I possibly attached the downstream and upstream tubes to the sensor in the wrong order but I'm pretty sure I got them correct. But still...the truck now sputters at initial throttle up and has less top-end power then before??? The replacement sensor was a Standard Motor VP13http://www.rockauto.com/catalog/moreinfo.php?pk=443992

This is the "New" updated design that is made out of plastic to replace the OEM design that is aluminum, but the orientation of the tubes is different. Now since I don't have a Ford Service Manual Illustration I am not 100% SURE I have the upstream and downstream tubes connected correctly. Additionally, one of the tubes is just not "quite" long enough and I think I might have a some amount of vacuum pressure leaking out...

 

[Earl43P]

http://www.tomco-inc.com/Tech_Tips/ttt35.pdf Has your answer.

If you need the high temp silicone tubing, Ford sells it.
Don't use any old hose, it'll melt.

 

[crashtestdummy]

So I finally got the tubes replaced and connected in the right order. Truck is running great so the DPFE was the issue. Thanks to everyone that offered help and suggestion, I really appreciate it. Have a great Turkey Day everyone!