Surge, Stall, Hard Start

03-30-2007, 11:03 AM
First off I want to thank this forum. Because of you all I have been able to complete tasks that I would not have even considered prior to experiencing your insight. I have learned a tremendous amount and I thank you.

Now my issue- I have a 99 amigo with 85,000, it is a 4x4 with the 3.2 V6. It has the same problem as many before me but I just can't seem to completely resolve the problem. The truck needs gas when starting warm. It will surge at idle speed from time to time. I will stall periodically.

I have replaced the following parts or serviced parts in order over a 4 month period. 1. Mass Air Flow 2. Cleaned EGR Thoroughly. 3. Replaced PCV and Grommet. 4. Replaced Intake Manifold Gaskets (both upper and lower). 5. Cleaned the Intake Air Control. Used clening kit to wash and oil the K&N Air Filter.

The problem improved when I cleaned the IAC so I wonder if it needs replaced or should I move on to the fuel pressure regulator or the MAF sensor?

Please, I ask for your wisdom and I am sorry for the lengthy post. I just want to be thorough so there is limited confusion. Thank You

03-30-2007, 11:17 AM

My guess is the fuel pressure regulator. I had the same issue recently and thought it was that. The dealer leak checked the intake gasket and found it was broken again (once at 55k and again at 77k).

If you torque the bolts too much the gaskets tend to break. Isuzu has changed the torque specs on the intake bolts 3 times .....

03-30-2007, 09:29 PM
I am with you Ryan-You know what is really ironic? When I first started having this problem, I read this forum as an outsider and all threads directed me to the fuel pressure regulator but all my "friends" around here said otherwise. Who are my the guys looking out for my best interest? All of you. Did your symptoms stop when you replaced the fuel pressure regulator? Thanks

Concerning the IMG. The torque specs have been revised to 13 ft/lbs right? I hope so.


04-05-2007, 11:19 PM
Update-I installed new fuel pressure regulator. I bought it at O'reilly for $42. Instantly I new my amigo was cured! I seriously about started weaping. The frustration is finally over!
The only hard part installing the FPR was getting the snap ring back on. The observation that I made is that even though the FPR and the snap ring are round, the ring has to go back exactly as it came out.

Anyway thanks to everyone that posts here. Now I shall move on to the problem with the fuel sending unit so my gas guage will work again.

06-18-2007, 08:35 AM
Hey I have a similar issue with my 2001 Rodeo Sport (AKA Amigo)... I have a surging issue while the car is in park during idle. It surges up to 2,000 RPM and down again a few times then smooths out. Sometimes it can do this for up to a minute. At times the car will also sputter/choke during "warm up" and may even die once or twice during the warm up process but once warm the engine runs fine. I have cleaned the EGR, cleaned the MAF, replaced the PCV, air filter and spark plugs (with the stock ION sensing ones). I plan to pull out and clean the O2 sensors to see if that helps. Since you have gone through a lot recently I figure I would see what you thought.

I see that you repaced the FPR too. This was something that I was not looking at. How was the replacement process on that part... quick and easy??? LOL

Thanks for any info... as you know it is very much appreciated.

Best regards all!

John Gyver

06-19-2007, 12:07 AM
Hey John, I strongly suggest replacing the fpr, it is easy to access, and fairly simple to replace. The only tool you need is a snap ring tool. I struggled with re-fastening the snap ring but I am convinced it was because I bought a cheap snap ring tool. Buy a good one for $15-$20 and the ring won't slip. The whole process should take less than an hour.

I can't even begin to tell you how I feel your pain and frustration. I can tell you how good my amigo is responding to the new fpr. It is like a brand new truck. I get 6 more miles to the gallon and burn less oil. All in all it just feels like I can rely on a consistant vehicle that I love.

The only other possibility I see with your problem could be the IMG. However, start with the fpr. You will know instantly after replacement if you are fixed.

Please let me know your outcome and if there is anything else I can do to help.

Be Well John,
Regards, Ron

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