motor surging problem

[bobo6750]

I have a 95' , I have a chip a k&n filter,and headers thats it. my problem is that sometimes at idel while in gear and, at a stop the motor's rpm's will start to drop and raise about 200 to 300 rpm's. It only happens once in a while and dosen't matter if the motor is cold or hot. A couple of my friends at home told me it's probaly my chip. But I never heard of a chip doing that. Hope somebody outhere can help

thanx

 

[SLightning]

i have had this problem at one time it turned out to be a bad superchip they did replace it though also had a bad tps do this

 

[stryfe]

mine does the same thing, or did. i ran a shot of injector cleaner through a tank, and i cleaned the HELL out of my throttle body. it doesn't do it nearly as bad now.

hence i think dirty fuel system was causing mine.

 

[AustinL]

It depends what kind of surge you are talking about. Most of these truks have an idle surge evident in drive or neutral. It was kind of a mystery for a long time but recently a member posted that when he replaced his ignition module that his idle surge promptly went away. Hopefuly he will read this thread and reply. I have not tried the ignition module yet but my truck doesnt have a chip and it does surge very definately. More of a variation than a surge but idle is not smooth by any stretch. Another guy said that with a diagnostic on the truck that the timing would spike causing the problem. I am unsure if the two will go together but I believe we are closing in on the problem. I do not think it is your chip however.
Corey

 

[huffentuff95]

I heard that a cause might be the Idle Bypass Valve, they get carboned up or the electronics go bad

 

[93 Red L]

mine just started doing this.....and I just replaced the o2 sensor??

 

[rubicon]

Mine's doing the same thing and I posted a thread on it a couple of weeks ago. I got a lot of replies including the 02 sensor etc. I think mine is due to the 24# injectors on the stock Speed Density without a chip. I figured a chip would take care of it. Could it be a faulty chip? I still have to purchase one so I am interested.

BTW, mine shifts really hard at times and the check engine light comes on once in a while. all these symptoms occured after the injector swap.

John.

 

[93 Red L]

I bet your's is running real rich with the 24's and no chip to support them.

 

[stryfe]

im a liar! mine is still surging.

 

[AustinL]

Let's all swithch out something and see what works first.
Corey

 

[93 Red L]

well I have already done the o2....

 

[AustinL]

welllll did the o2 fix the problem or not? dont leave us hangin!

 

[93 Red L]

nope....I should have some new exhaust on here soon too.

 

[93 Red L]

Anyone have an update on this??

 

[Heavy_Metal]

I have this same problem. I have had my 93 truck for four years. It has had the surging problem off and on the whole time I have owned the truck.

My friend had a 94 Lightning for five years, which off and on had the same problem. In addition to the surging we both had what I would refer to as a miss. Not at idle but when in neutral. Revved up to any RPM above idle and held. We could both also feel this miss driving normally down the road. It seems to me the more moods, and timming used (12 degrees or more) the more the miss and surge is enhanced. Mine has had the miss since I have owned it. I have replaced everything but the cigarette lighter to fix it.

Meaning Plugs, Ford fuel filter (I am on the fourth one now) Crane Hi-6 TR with PS91 coil, Ford 02 sensor, Ford Motorsport wires, new Ford Lightning distributor Cap. $42.00 dollars from the dealer. The cap is black with alum terminals. Everything I had previously put on it had Brass terminals.

None, of the above items helped!

I can say when the truck will not idle at all, dies at a stop light, idles extremely low, or has a whistle sound. It is probably the Idle Air Bypass. That is what mine did in addition to all the above. I also checked for vacuum leaks at the time, and did not find any.

Yes, I replaced the idle air bypass! Bought the part from Ford. Had my mechanic put it on, and the truck is running exactly like it did before. Part replaced 3 years ago.

When the Idle Air Bypass was replaced, my truck no longer whistled, died at a stop. “Surged “extremely” bad. Or idled at a very low RPM.

My point here is this; I think the Lightning’s just do this. It is normal! I think this for two reasons:

1) Too many of us complain about the same problem.
2) Most everyone that has posted about this problem says their truck run like a “RAPED APE” at Full Throttle. Which is what counts with me.

I hope someone can figure it out. I have spent way too much money on this one!
Mike

 

[93 Red L]

Well I was wondering how many have replaced everything that the recall is to replace and still experiencing this problem. I was planning on buying a new FPR here sometime soon. Just seems it isn't getting fuel on occasion.

 

[Subliminal Message]

I read a recent post, don't remember whom or what, that said it was the fuel pressure regulator that caused the surge. As I don't know where mine is, I'm just storing that information in my head.

Damon

 

[Zarr]

FWIW....mine surges in park and neutral as well. Not too bad, but enough to be noticable. I'm going to replace my Idle Air Control Valve this weekend and see if that fixes it. All Ford 351's and especially the Lightnings are known for this part going bad. I replaced the IAC on my old Bronco when it was doing the same thing and the problem went away. Generally when a TPS goes bad, you will know it. Lack of power, vehicle constantly dying at idle, and irratic shift points are all pretty good indicators that your TPS has gone south. If the truck is simply surging at an idle, I would start with the IAC. Running a can of injector cleaner through the tank and wiping the throttle body down with some carb cleaner can't hurt either.

I will let everyone know if the IAC fixes my problem this weekend...

 

[stryfe]

i changed this -

cap
rotor
exhaust (magnaflows)
airbox (thanks Sal from power surge!)
cleaned the hell out of the throttle body

it no longer surges. but the weather is warmer so there is another variable to consider. speed density is weird.

 

[93 Red L]

Yeah...I have done basicly the same thing along with new o2. Still does it.