Surging @ cruising speed.
Thread Starter
Junior Member
Joined: Aug 2007
Posts: 69
Likes: 0
From: Visalia Ca
Car: 86 IROC spts cpe conversion.
Engine: 89 L98 TPI since 2000.
Transmission: NOW A T-5 as of 3/19/08
Axle/Gears: 373s
Surging @ cruising speed.
This is happening on my car, as well as my cousins car.My car L98 350 TPI Full tune up / with injectors.http://imaging.lefora.com/reduce/?ur...a15e0/cam2.bmp Starts great.accelerates great. while at cruising speeds the car begins to surge wether it's in first or 4th.I have to accelerate to relieve the surge. He has a 305TPI. I have the 350. Any suggestions?Both cars have had full tune ups. fuel filters, plugs, wires, caps, rotors, and coils. Mine has new 20lb injectors
http://imaging.lefora.com/reduce/?ur...307e1/cam1.bmp
http://imaging.lefora.com/reduce/?ur...307e1/cam1.bmp
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: Surging @ cruising speed.
It could be one of 50 different things, but since you've already replaced the injectors and the fuel filter, I would guess you have an intermittent open in the fuel injector wires.
Thread Starter
Junior Member
Joined: Aug 2007
Posts: 69
Likes: 0
From: Visalia Ca
Car: 86 IROC spts cpe conversion.
Engine: 89 L98 TPI since 2000.
Transmission: NOW A T-5 as of 3/19/08
Axle/Gears: 373s
Re: Surging @ cruising speed.
Do you think it could be the pressure regulator? Would a variance in the fuel pressure do this kinda thing?
Senior Member
Joined: May 2002
Posts: 845
Likes: 0
From: Northern California, Redding
Car: Red 1987 IROC Convertible
Engine: 305 LB9 TPI
Transmission: T5 5-Speed
Axle/Gears: 9-Bolt 3.45
Thread Starter
Junior Member
Joined: Aug 2007
Posts: 69
Likes: 0
From: Visalia Ca
Car: 86 IROC spts cpe conversion.
Engine: 89 L98 TPI since 2000.
Transmission: NOW A T-5 as of 3/19/08
Axle/Gears: 373s
Re: Surging @ cruising speed.
It happens all of the time. whether or not the AC is on. Now, both cars have NOT had the regulators replaced. They're original. And or, would this be a symptom OF a bad regulator?
Member
Joined: Jun 2009
Posts: 105
Likes: 0
From: south coast mass.
Car: 1991 camaro z28 convertible
Engine: 383 tpi
Transmission: t5
Re: Surging @ cruising speed.
i am having the same problem any other ideas.......i have new jet fuel pressure reg...so i would doubt its that
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Senior Member
Joined: Aug 2008
Posts: 710
Likes: 32
From: pensacola florida
Car: 1989 Firebird Formula
Engine: 5.7 LS1
Transmission: 4L60E
Axle/Gears: 3.27
Re: Surging @ cruising speed.
is it speedy density or maf? could be possible the ECM could be showing signs of going bad, its rare, but ive seen it happen. id check the fuel pressure, or check the vacuum lines. sounds very weird though
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iTrader: (4)
Joined: Nov 2007
Posts: 187
Likes: 0
From: Manitoba, Canada
Car: 91 Formula
Engine: 305 TPI
Transmission: T-5
Axle/Gears: stock
Re: Surging @ cruising speed.
My 91 305 TPI has had the exact same problem for years! It's especially bad around 1000-2000 RPM, in the lower gears. Was your car giving you any codes? Just wondering how you knew it was the MAP sensor. I've changed CTS and O2, car has good tune up, 18 inches of vacuum, 40 psi fuel, no codes, etc.
I don't know about your car, but mine thuds back and fourth as the revs bounce about, its extremely annoying.
I'm seriously out of ideas, was about to post a new topic but I'll see if there is any additional info here.
I don't know about your car, but mine thuds back and fourth as the revs bounce about, its extremely annoying.
I'm seriously out of ideas, was about to post a new topic but I'll see if there is any additional info here.
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