surging while cruising

[obrut]

3rd gear will eliminate the computer signal to the sol. and if you have a means of monitoring your fuel pressure at speed, you should be able to eliminate a pump problem. Have you ck'd for and cleared any codes?

I though there was still lockup in third, I will have to try in third and seen what happens. I do have a KB hood mount fuel pressure guage that is rock solid while cruising and my scanmaster doesn't have any codes stored.

It's not a 1/4 turn, just very slightly move it a 1/4 inch. I must have had it set on the edge of the window of operation, I had moved it too far and created a pig rich cold start condition that took me a while to figure out. Good question about the cam, I wish I would have stayed with the stock cam however I was talked into the larger cam by the engine builder so I could grow into the combo.............dumb I know but live and learn.

Yep good catch, I typed it wrong but I know what you were saying, you only turn it a little - about a 1/4" distance.

 

[John Larkin]

I had a programmable chip once and it surged in lockup at a steady highway speed, around 55. It needed more fuel since it was lean. Just my experience. Your situation may be different. You could always write your chip maker and ask the question. He may have an answer since he deals with many people and many situations.

 

[Rebel 1]

My 87 T used top have a light surge locked up in 4th at 45-50 mph. Cleaned MAF

 

[obrut]

I had a programmable chip once and it surged in lockup at a steady highway speed, around 55. It needed more fuel since it was lean. Just my experience. Your situation may be different. You could always write your chip maker and ask the question. He may have an answer since he deals with many people and many situations.

I will add this to my list, I have a PTE chip that I was using before the TT chip, I might put that back in and see if there is a difference.

 

[Scott89TTA]

Looks like mine was the ignition module...see my post in the TTA section. Keeping my fingers crossed!

 

[obrut]

Looks like mine was the ignition module...see my post in the TTA section. Keeping my fingers crossed!

Cool, I hope it works out for you. I've had no time this week to work on my car, maybe this weekend I can get back out there.

 

[Scott89TTA]

Cool, I hope it works out for you. I've had no time this week to work on my car, maybe this weekend I can get back out there.

Thanks...good luck!

 

[dand]

I didn't have the symptoms as severe as what you are describing but I had surging at cruising highway speeds. after running turbolink while driving, I noticed the vss was reporting erroneous vehicle speed while cruising causing the engine surging. Replaced the unit and after months of trying to figure out the problem, issued solved. Worth a shot to check out the to make sure it is operating correctly.
Hope that helps
Good luck

 

[we4Mateo]

Check to see if there is a lean cruise operation in your chip too. If the plug gap is small and/or ignition system isn't up to par, then the lean cruise surges like that at those speeds. A hot ignition with a wider gap cured my issue. Turning lean cruise off with a good stock ignition module would clean it up too.

 

[Rodney87GN]

Looks like mine was the ignition module...see my post in the TTA section. Keeping my fingers crossed!

Awhile back, I also experienced similar cruise surging on the highway (around 65 mph) as yours and obrut's. After swapping out a cam sensor, coil pack, verifying fuel pressure, voltage, wiring, etc...turns out it was my ignition module. Also it would only surge when outside temps were warm...it wouldn't do it on a cold morning. Otherwise my car ran fine.

Hopefully the ign module will fix for your problems.