40 mph surge help
05-15-2009, 07:41 AM
#1
Thread Starter
Join Date: Oct 2008
Location: Texas
Posts: 28
40 mph surge help
Did a search, so I'll try again for help. Idles perfect at about 6, starts off smooth until I get to 40 mph, 4th gear, then the car wants to surge and buck if I just drive steady. When I accelerate up to 50 mph, smooths out perfect. As long as I am accelerating, it does not surge.
Cleaned the IAC, heard mention of cleaning the MAF, any other thoughts?
Richard
Cleaned the IAC, heard mention of cleaning the MAF, any other thoughts?
Richard
05-15-2009, 10:41 AM
#4
2nd Gear Member
Join Date: Feb 2007
Location: Pennsylvania
Posts: 262
It could possibly be from the chip...my car does the same thing...its because of the EGR flow, but my problem is because of the aftermarket heads i have on it. After i got it dyno tuned it reduced the bucking considerably but it still does it if i hold steady just like your description. If you want to give it a shot you can disconnect the vaccum line on the EGR valve and block it off, your check engine light will eventually come on but if it changes the bucking at all you could have the same flow problems that i had...but considering our mod list is considerably different anything is possible...
Keep in mind this is just a suggestion related to mods....a regular driveability concern could still be possible at 110k that could be fixed with a simple tune up even. Go through the regular checklist for tune up items if you havent already done any of them first, and you could always try that EGR vaccum line and see if that makes a difference.
Keep in mind this is just a suggestion related to mods....a regular driveability concern could still be possible at 110k that could be fixed with a simple tune up even. Go through the regular checklist for tune up items if you havent already done any of them first, and you could always try that EGR vaccum line and see if that makes a difference.
05-15-2009, 10:54 AM
#5
Thread Starter
Join Date: Oct 2008
Location: Texas
Posts: 28
It could possibly be from the chip...my car does the same thing...its because of the EGR flow, but my problem is because of the aftermarket heads i have on it. After i got it dyno tuned it reduced the bucking considerably but it still does it if i hold steady just like your description. If you want to give it a shot you can disconnect the vaccum line on the EGR valve and block it off, your check engine light will eventually come on but if it changes the bucking at all you could have the same flow problems that i had...but considering our mod list is considerably different anything is possible...
Keep in mind this is just a suggestion related to mods....a regular driveability concern could still be possible at 110k that could be fixed with a simple tune up even. Go through the regular checklist for tune up items if you havent already done any of them first, and you could always try that EGR vaccum line and see if that makes a difference.
Keep in mind this is just a suggestion related to mods....a regular driveability concern could still be possible at 110k that could be fixed with a simple tune up even. Go through the regular checklist for tune up items if you havent already done any of them first, and you could always try that EGR vaccum line and see if that makes a difference.
05-15-2009, 03:35 PM
#7
1st Gear Member
Join Date: Jul 2007
Location:
Posts: 99
Sounds like the DPFE (Delta Pressure Feedback EGR) sensor on the EGR system has gone bad, (although that usually gives a code) like previousle said take of the vaccuume line to the EGR, plug it and see if the surging goes away. If that dosen't seem to fix it try the TPS
05-18-2009, 06:22 PM
#8
Thread Starter
Join Date: Oct 2008
Location: Texas
Posts: 28
Sounds like the DPFE (Delta Pressure Feedback EGR) sensor on the EGR system has gone bad, (although that usually gives a code) like previousle said take of the vaccuume line to the EGR, plug it and see if the surging goes away. If that dosen't seem to fix it try the TPS
05-20-2009, 02:36 PM
#9
2nd Gear Member
Join Date: Feb 2007
Location: Pennsylvania
Posts: 262
just plug the end of the vacuum hose once removed from the EGR valve. as far as the DPFE sensor going, im almost positive that sensor is only there to monitor the fact that there is indeed flow or no flow, at least thats how it used to be on some older models, and every instance we've come across that was a DPFE always set a MIL code, even if it was for the high temp hoses it still set a code