Violent Bucking at Throttle, Smooth Idle

[cmt45]

My Explorer started bucking as I was accelerating so I let off the gas and it ran smoothly but anytime I give it throttle it starts bucking again. I put a code reader on it and got a 327 code (EGR not at minimum voltage). I replaced the DPFE sensor and I am still having the same problem.

Any suggestions? Did I need to do something else also?

Thank You!

 

[koda2000]

when's the last time you changed your fuel filter? sounds like a fuel delivery problem.

 

[cmt45]

Not since I have had it which has been a year now. It is worth a try but that wouldn't cause the "EGR low voltage" code to appear...would it?

 

[Jason94sport]

might be unrelated. Check your spark at the coil pack. Check your spark plugs & wires.
And your 93 has EGR?

 

[cmt45]

I put the code scanner on again after replacing the DPFE sensor and got an all clear code. But it is still bucking but not as bad as before. I am wondering if I just have such bad carbon build up in the EGR tube that it is causing bad readings. And to Jason94sport, yes I have an EGR. Thanks everyone.

 

[Jason94sport]

Must be a late late late 93. Cause EGR wasn't supposed to be until 94 model. One of those great mid 90's ford things...

 

[cmt45]

Does that include Fords manufactured in Canada?

 

[cmt45]

Okay...Here is the update. I checked the manufacturing date of the Explorer and it is 09/93. Is that a 93 or a 94? Either way, there is definitely an EGR setup on it. I took apart the valve and tube, cleaned it all really well and put it back together. I also replaced the fuel filter. Took it for a test drive and it seemed to do good until it got heated up then it started bucking on throttle again. I ran the codes again and the EGR low voltage code was gone but now I have a 172 and a 136 O2 sensors running lean. Any thoughts?

 

[Anime]

93-94 Had EGR. It was the late '92's that were introduced as 93 models but didn't have the EGR.

Have you cleaned the MAF? Sounds like you also might want to change the fuel filter, maybe even the fuel pump, and check that the fuel system pressure is ok. If it's not getting enough fuel it'll give a lean condition.

Could also be dirty fuel injectors from using low-quality fuel. Get a bottle of techron or Fuel Injector Cleaner, and use some top tier detergent gasoline from now on. It takes awhile, but eventually clean injectors make a difference.

 

[cmt45]

I changed the fuel filter when I cleaned the EGR tube and valve. Out of curiosity, if I unplugged the MAF sensor and it still did the same thing does that mean anything? When I first bought this truck it started to have a very rough idle so I unplugged the MAF and it ran smooth from that point on. I replaced it with a used one shortly after that and it fixed the idle problem when I plugged it back in. So I thought this might be that problem again and unplugged it again but it still bucked. How can I clean the MAF, alcohol and a Qtip?

 

[acschilling]

Alcohol maybe, I just bought some electrical parts cleaner. Do not bend the tiny filaments near the tip. Also, make sure everything is dry before plugging stuff back into their harnesses.

 

[Anime]

Best way to clean the MAF is just spraying the sensor element with electronics cleaner or air intake cleaner or even carburetor cleaner. I wouldn't make contact with it using a swab or anything else. I usually spray it once, let it dry, spray it again, let it dry, and so on until it's completely clean. Removing the MAF housing and cleaning it up inside, including the wire screen, seems to keep the MAF itself cleaner longer as well.

 

[cmt45]

Okay, I cleaned the MAF sensor element with electronics cleaner. Now to say it made no difference would not be true. When I first took it out for a test drive it ran like a champ, better than it ever has before. But once the temp reached the NO in NORMAL the engine light came on and it started dogging again. Then I got some speed going the temp dropped below the N and the engine light went off and it ran great again....and so on and so on. This issue has to be temp related. Does the Air Charge Temp sensor control air/fuel ratio? I am stumped.

 

[cmt45]

This afternoon I let the truck run idle and hooked a vacuum pump to the EGR valve, put 5 in. Hg of vacuum and the truck almost stalled out. This tells me that the EGR valve is opening and closing properly. So next test was hook up a vacuum pressure tester to the vac line coming from the EGR solenoid and when I did a slow acceleration it pulled just over 5 in. Hg of pressure but at higher RPMs it would flutter in and out from 5 in. HG down to 0 and back up to 5...does this mean my solenoid may be bad? Should it hold a steady 5 in. Hg when accelerating?

 

[TheGaginator]

I have been having the same problem intermittently but then it slowly got worse and worse. New fuel filter did nothing. My new Fuel pump will be here in a couple of days and ill let you know if it fixes the problem. My fuel gauge has been non functional since ive had my explorer so i purchased the entire pump/sender kit for only $70 on ebay.

 

[cmt45]

Thanks Gaginator! I am looking forward to hearing if the new pump fixes your problem. I am really stumped about this problem. I have no vacuum leaks, my EGR valve and regulator test good, I've cleaned my MAF sensor, and replaced the fuel filter and still have no changes. I will keep you updated if I have any new results.

 

[TheGaginator]

Just checked the tracking number and the fuel pump will be here on the 6th. I'm going to cut a hole in the floor instead of dropping the tank because I don't want to mess with rusted bolts underneath. I'll keep you updated!

 

[TheGaginator]

Alrighty. Got the pump in the mail this morning and put it in after work. One of the easiest fuel pumps that I have done. Cut an access hole under the drivers side rear seat and removed the pump. Luckily my fuel line connectors came off pretty easy with the fuel line tool. Gave the fittings a couple hits with my pliers to loosen up rust and such. Blew everything off very well then took the tank lock ring off with a flat head and a hammer. This was the hardest part. Extremely rusted. Used a lot of wd40. Cleaned all and put new pump in. To re-install the piece of metal that I cut off, I drilled holes on the metal piece, and the outside of the floor where it came from and used zip ties to hold it in. Then duck taped it up. For what I use my Explorer for, I don't need it to look pretty. I don't even have carpet or anything in it so it made that part a bit easier. Pictures uploaded on page 2. Took me 2hrs and I was really taking my time.

 

[Turdle]

Must be a late late late 93. Cause EGR wasn't supposed to be until 94 model. One of those great mid 90's ford things...

93-94 Had EGR. It was the late '92's that were introduced as 93 models but didn't have the EGR.

Have you cleaned the MAF? Sounds like you also might want to change the fuel filter, maybe even the fuel pump, and check that the fuel system pressure is ok. If it's not getting enough fuel it'll give a lean condition.

Could also be dirty fuel injectors from using low-quality fuel. Get a bottle of techron or Fuel Injector Cleaner, and use some top tier detergent gasoline from now on. It takes awhile, but eventually clean injectors make a difference.

1993 California trucks had egr, wired in cam sensor , sequential injectors, and, dual o2 sensors

 

[cmt45]

Hey Gaginator, thanks! I would like to see those pics. So I assuming the fuel pump fixed your problem? I replaced my MAF sensor and that removed my "O2 Lean" codes but now I have the "EGR PFE sensor voltage out of range" code again. I also had a bad thermostat which caused the truck to overheat on Tuesday. So I am thinking that the New (less than 2 weeks old) DPFE sensor might have been fried due to the overheating. I can also hear crap rattling around in my CAT, which may or may not be part of problem but definitely needs to be addressed. Thanks again to everyone with their help!