4.6 Problems

acb92sc

Registered User
I Have A 95 Lx W/ A 4.6 V8. It Starts, Revs To 1200 Rpm Or So, And Dies. You Have To Hold It At 1300 Rpm Until It Accelerates Itself, And Then In Restores To Normal Idle And Drivability. I Assume That It Goes Into Open Loop At This Point. There Are No Codes Being Thrown, And Once It Warms Up It Runs Like A Champ. If It Sits Too Long, It Goes Right Back To Its Problems. Any Inclinations, Anyone?
 
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fix for your problem.

I would clean the maf and see if that helps. If that dose not help do a starting fluid test. spray around the intake guaskets and if the engine speeds up you have a vacuum leak. This is what I have found to be prevelant on the 94-95 4.6 cars. There is a rubber vacuum T on the passanger side on the rear of the manifold near the torottlebody. It dryrots and develops a hole in it allowing a vacuum leak. I doubt that the part is available but you can make a replacement using a plastic t and a short piece of rubber hose. good luck. steven
 
Nothing When It Shuts Off, But When The Idle Is Fluctuating Up And Down, It Makes A Weird Whining Noise.
 
I too think the MAF is dirty. I would also check the IAB on that. I think you have two problems. The MAF usually does not (in my expirience) cause the car to die. It just wont go. The IAB on the other hand will kill it. Take a screwdirver and do a GM tap test on the IAB. Just give it a good thump. If it works you are slick. If not I thinkn you will have to pull the down pipe off of the intake and look to see if there is carbon blocking the IAB flow. This USUALLY trips a code. It WAS a common problem in those intakes. If I were you, I would do a PI swap and eliminate that intake all together.

Chris
 
Its My Moms Daily Driver, So Im Not Looking Forward To A Pi Swap. I Already Replaced The Iac/iab Motor, So It Isnt That Either. Did I Ever Mention That I Hate Fords Some Times?
 
It sounds like it might be a problem with your IAC. It could be a sensor, so I would test ECT and TPS first, but then I would try swapping with a junkyard IAC and see if the problem goes away.
 
The ECT is the engine coolant temperature sensor. The EEC relies heavily on that to determine fuel-air mixture (and maybe timing) at startup. (Because it can't use the O2 sensors until they warm up.)
 
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