95 5.0 issues

[955.0]

I have a 95 GT 5.0 of course, under hard accelration sometimes it will brake up at higher rpms and it always smells like it's running rich. After shes warm if I stop at a store or some were and shut her off them come back out and start it and leave it will run like a rocket for about 4th gear by that time what ever my problem is its warmed back up just enough to regain the topend brakeup. And on a load sometimes my valves chatter but not always, like when I leave some were after its already warm and I just started it back up when it is running like a rocket the valves don't make a noise. would you have any idea what it is. I have underdrive pullys, a K&N filter, headers, BBK offroad H Pipe, 40 series Flowmasters and a MSD cap and rotor and wires with autolight plugs. Can you help me please?

[wick]

The autolite plugs for one. You should always run motorcraft in there unless you have power adders. How long has it been since you did the tune up?

[955.0]

The autolite plugs for one. You should always run motorcraft in there unless you have power adders. How long has it been since you did the tune up?

It's been probally 2 weeks since the tune up, but I've had the problem before the tune up. Thank you

[wick]

Engine light? My O2 sensors were bad causing a similar issue.

[955.0]

Engine light? My O2 sensors were bad causing a similar issue.

Check engine light on after you let off the gas, after hard accelration I changed the o2s.

[SAC81]

The autolite plugs are absolutely fine. I've always run autolite plugs, and plenty of other 5.0 guys do the same. They are basically the same thing as Motorcraft plugs anyway...both copper cores.

As to the issues you are experiencing, I'm going out on a limb and saying it's about a 99% chance that you have a bad or dirty MAF. I, and MANY other 94-95 owners, have gone through what you are current experiencing.

The reason why it begins acting up after running for a few minutes is that during warm up, the car relies on the 02 sensors to develop a proper A/F ratio. After warming up, the car primarily relies on the MAF...and since you're is screwy, the A/F ratio is too. The "valve chatter" you think you are hearing is most likely spark knock, caused as your bad MAF alternates between a very rich and a very lean condition.

Swap your MAF with another and see if it fixes the issue- I betcha it does.

[coralcoupe1993]

Yea, clean up the MAF. I was in a 95 last year that had the same issue. Get-er-Done

[955.0]

Thanks guys I'll check that out to day!!

[955.0]

Well guys thats not the problem I changed it today. Do you think it would be my IAC valve? Thank you!!!

[Rodeheaver's]

Well guys thats not the problem I changed it today. Do you think it would be my IAC valve? Thank you!!!

No, the idle air control valve only does anything below 1500 rpms, what kind of gas do you run?

[955.0]

I run high test, would you have any other idea what it might be? Thank you

[94Cobra]

I would pull the codes out of the computer via the engine compartment plug in harness. I bought a $25 code puller from Advance and it works great for pulling codes. It performs several tests, including a sequential fuel injector test that will determine which cylinders are not firing. I used this test to determine that I had a bad fuel injector once. Most likely you have some trouble codes stored - you need to find out what they are to help determine what the problem(s) are. You might also want to check your fuel pressure with a gauge if you haven't already. Can you make the break-up happen when the car is in neutral? If so, try to get it to occur with a fuel pressure gauge attached to the fuel rail.

[Rodeheaver's]

check you r fuel preasure, try and check it while idleing and somehow while you are going down the road, and be sure that when you smack the throttle the pressure goes up like is supposed to, pressure should be between 35-45lbs

[955.0]

it does not have the brake up when the car is not in gear just going down the road. Thank you

[Killercanary]

So its a high temp, load based breakup. The 94-95's are notorious for pinging (detonating) even at stock initial timing. A dirty MAF is often the biggest cause. Is it truely a detonation problem, or does the car just break up like hitting a rev limiter? The stator often acts up right before it quits, and this usually happens when its hot.