Slight surging when foot is off the throttle..

RE: Slight surging when foot is off the throttle..

Hi Stanley, I would think it is the IAC for a normal daily driver. But with your Mark, I would try some fresh BP premium fuel, and Valvoline SynPower entire fuel system cleaner (the $10 bottle) first, since your Mark spends alot of time sitting around. I would also do a couple safe WOT blasts to wake it up. Just watch out for the CHP ;) . Good luck!
 
RE: Slight surging when foot is off the throttle..

[div class="dcquote"][strong]Quote[/strong]
I would also do a couple safe WOT blasts to wake it up. Just watch out for the CHP ;) . Good luck!
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I already did a wide open throttle blast it in December it cost me $219 for the ticket and 35 for the traffic school........ Damn Radar Guns... thanks for the advice.

Stanley E. Roberts
President/Founder
http://www.GoldenGateMark8.com
http://www.We8there.com
 
RE: Slight surging when foot is off the throttle..

Surging is a tough malady to pinpoint. From AllData...

Engine - Lean Driveability Symptoms
Article No.
98-23-10

11/23/98

MASS AIR FLOW (MAF) - SENSOR
CONTAMINATION - SERVICE TIP
____________________________________

LINCOLN-MERCURY:
1990-97 COUGAR
1991-99 CONTINENTAL, GRAND MARQUIS, SABLE, TOWN CAR, TRACER
1992-94 TOPAZ
1993-98 MARK VIII
1995-99 MYSTIQUE
___________________________________

ISSUE
This TSB article is a diagnostic procedure to address vehicles that exhibit lean driveability symptoms and may or may not have any Diagnostic Trouble Codes (DTCs) stored in memory.

ACTION
Follow the diagnostic procedures described in the following Service Tip. The revised diagnostic procedure is a more accurate means of diagnosing the symptoms.

SERVICE TIP

MASS AIR FLOW (MAF) DISCUSSION

MAF sensors can get contaminated from a variety of sources: dirt, oil, silicon, spider webs, potting compound from the sensor itself, etc. When a MAF sensor gets contaminated, it skews the transfer function such that the sensor over-estimates air flow at idle (causes the fuel system to go rich) and under-estimates air flow at high air flows (causes fuel system to go lean). This means Long Term Fuel Trims will learn lean (negative) corrections at idle and learn rich (positive) corrections at higher air flows.

If vehicle is driven at Wide Open Throttle (WOT) or high loads, the fuel system normally goes open loop rich to provide maximum power. If the MAF sensor is contaminated, the fuel system will actually be lean because of under-estimated air flow. During open loop fuel operation, the vehicle applies Long Term Fuel Trim corrections that have been learned during closed loop operation. These corrections are often lean corrections learned at lower air flows. This combination of under-estimated air flow and lean fuel trim corrections can result in spark knock/detonation and lack of power concerns at WOT and high loads.
________________________________________

Symptoms

^ Lack of Power

^ Spark Knock/Detonation

^ Buck/Jerk

^ Hesitation/Surge on Acceleration
________________________________________
 
RE: Slight surging when foot is off the throttle..

Been a while since I've been here. Mine does the same thing. To me, it almost feels like the torque convertor is not unlocking fast enough. Try lightly applying the brake with your left foot right at the point of decelleration. Only apply the brakes enough as if you were to disengage cruise control. See if that helps you diagnose.

Tony
 
RE: Slight surging when foot is off the throttle..

[div class="dcquote"][strong]Quote[/strong]
Been a while since I've been here. Mine does the same thing. To me, it almost feels like the torque convertor is not unlocking fast enough. Try lightly applying the brake with your left foot right at the point of decelleration. Only apply the brakes enough as if you were to disengage cruise control. See if that helps you diagnose. Tony
[/div]
I just needed to add a little sea foam and all is well... thanks
Stanley E. Roberts
President/Founder
http://www.GoldenGateMark8.com
http://www.We8there.com
 
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