Yet another surging problem question

[kennyz]

As some of you may know, I have been trying to solve the dreaded surging problem for some time now. New plugs, wires, used ignition module and coils, and fuel filter. I have now found that it still surges while the transmission is in Drive. Does this help to eliminate any of the causes of the problem or help in diagnosing it??

[96 SSEi]

hi, I believe you would greatly benefit from a scantool that will give you basic operating environment -
fuel trims, ect, maf/map and o2 volts - I got a cheap - under 100 from wally mart
roadi ngs 100 - well worth the price.

please unplug the Maf and see if you issue improves....

[redzmonte]

How bad does it surge? Is it like a miss fire surge or just a slow smooth surge?

when does it surge? up hill, flat ground, accelerating, coasting, holding a constant speed?

Have you cleaned your maf anytime recently? is there a screen in the MAF/Throttle body still?

If you can scan it, that may help isolate the issue to something like bad/dirty maf or slow O2 sensor..

[kennyz]

It`s a steady surge, will do it uphill or on flat ground if I`m accelerating. I usually make it stop by either lifting off the pedal or downshifting into passing gear. It will do it in both OD and Drive.
I`ve scanned it on several occasions, no codes.
Once in a while it will throw a code for insufficient flow to the EGR but that`s not very often.

[redfury]

You probably have a blocked or partially blocked EGR tube. That will cause the surging. Take the tube off, there's no gaskets to worry about. Get some carb cleaner and blast it and break up the carbon. Ideally, take the entire throttle body off and get access to it easier and make sure the throttle body is clean as well.

[kennyz]

I`ve already cleaned the tube and the problem still persists.

[96 SSEi]

did you unplug the Maf?

[kennyz]

did you unplug the Maf?

Yes I did. It seemed slightly better but did not go away completely.

[96 SSEi]

you sure there are no codes at all? pending codes can be useful to detect the issue.

you can clean the IAC valve - right below maf on front of TB.

what rpm are you at idle, full operating temp - 200f? in park and in gear.

[kennyz]

you sure there are no codes at all? pending codes can be useful to detect the issue.

you can clean the IAC valve - right below maf on front of TB.

what rpm are you at idle, full operating temp - 200f? in park and in gear.

About 600 RPMs.

[96 SSEi]

can you swap the maf with a known good unit to test performance with new maf?

600rpm seems low it should be 750-850 iirc

[MKMike]

Check fuel pressure.
You may have a faulty fuel pressure regulator or a failing fuel pump.