[KK95GT]

I have this over in the 5.0 tech thread too, just figured two listings is better than one........

Looking for some diagnostic help on my ’95 GT 93,000 mile 5.0 motor with a stock intake system (except for K&N filter) and a Mac shorty / Flowmaster cat-back exhaust. In other words, a basically a stock original motor w/o many mods.

The car runs great except above 3000 RPM at wide open throttle. About 2000miles ago I had some intermittent starting problems so the fuel pump, idle air control valve, ignition control module (not the computer), ignition coil, and fuel filter have all been replaced. (Replacing the ignition switch finally fixed the problem….). The car has been fine up to about a month ago.

For normal everyday driving the car is fine. If you run it up to 4500 at part throttle it’s fine and it will run continuously (cruise) at 4500 without a problem. It’s when you punch it and try to rev it above 3000 RPM that it has a problem. In other words, it will run up to 4500 fine with a part throttle but if it’s WOT (floored from a take off) it will run up to 3000-3500 RPM and then act like it’s running out of fuel above approximately 3000 RPM. It will start to die and loose power at 3000-3500 but momentum will carry it up to about 4500 (starts acting up about 3000 but will still rev up to 4500) but by then it’s dying enough to slow itself back down. If you hold it WOT it will continue to slow itself back down just like it’s running out of fuel. If you back off to part throttle at any point it’s fine and will run at 3000, 3500, 4000, what ever you want, but as soon as you step back down to WOT it acts like it’s loosing it’s fuel flow and begins to die again. I really don't believe it's a fuel issue though so the best way to describe it is to say it feels just like a rev limiter is kicking in or the advance is being pulled waaay too far forward or something. It's like it's a rev/vacuum controlled type issue.

No check engine light is showing and the fuel pressure regulator seems to be operating ok (I have a fuel pressure gauge mounted on the rail and at idle the PSI bumps up with the vacuum line disconnected like it should). With a new fuel pump and fuel filter, new ICA, and new ICM in the car and the regulator appearing to work I don’t really know where to go from here. It strikes me as a computer control/signal issue or some sensor like maybe the throttle position sensor type issue. I just hate to just throw money at new parts (particularly the computer) and hope something fixes it.

Anyone had this problem and know how to fix it!

Thanks.

[Andx]

Have you cleaned your maf???

[dodgestang]

I had this problem in my 65 recently (except at a slightly higher RPM).

I would start strong. Hit 7500 shift into second....run strong...hit 6k and the car would just about die with no more power.

About 10 minutes later I figured out my alt. was completely dead and I was running off battery and basically running out of juice to power the MSD.

[KK95GT]

Yep have cleaned the MAF. Alternator is working fine too.

[larrylass]

Ok i just had this problem check this;
pull off the distributor cap and look for any black dust. your rotor vane could be hitting the magnetic sensor inside the distributor. the sensor should be stable and not loose. let me know what you find. Also theres a box on the passenger side of the radiator above the ABS junk called the CCRM "command control relay module"they are notorious for going out on the 95`s at about your mileage. This module has some control over your fuel delivery. Hope this helps

Big lar

[KK95GT]

Do you mean the ignition control module (I've already replaced this part) up on the inner fender just under the air filter or do you mean the black plastic box between the radiator overflow and the aluminum Bosch ABS directly in front of the air pump pulley? Never heard of a CCRM and the black box I see next to the ABS looks like it's a part of the ABS.

[95fiveoh]

It's a little black box with a wiring harness coming out of it. it is right behind the radiator where the coolant overflow resevoir is. try checking the timing too.

[95STANG_GT]

I had this exact problem and i just clened the MAF and the Idle Valvle and renplace the O2s and my proble gone maybe it can be the O2's, or just clean the MAF because the K&N oil get it dirty..

[KK95GT]

I had pulled the K&N and put a regular filter two weekends ago. I had also pulled the MAF apart and used carb cleaner and then alcohol on a Q-tip to clean the MAF. Unfortunatley no change.
IAC valve is only about 2000 miles old.
Not pulling any codes regarding O2 sensors so I hate to throw money at them.

No fault codes at all are showing so I'm stumped 'cause I would think codes would be showing for this problem!!

[95STANG_GT]

why you dont clean your IAC whit electronic cleaner,Your O2's are the stock ones i bought mine from summit NGK try that if not thake off the o2's and clean them look this are the o2's that i bought.. http://store.summitracing.com/partde...5&autoview=sku

[lxarlo]

ok i would see if you could get a hold of a code reader that can read voltages, and check voltages for the maf tp sensor, and fuel pressure under load. the maf and tp should be ranging from about 1 volt to about 5. 1 volt at idle and around 5 wide open throttle. it should not be above 5 volts. the tp you can check with a volt meter with the key on engine off and hand moving the throttle. make sure it changes appropriately with throttle position, and smoothly.

[KK95GT]

Was approx 1 volt at idle and 5 volt at WOT last I checked. Checked it while running though. I'll try it again KOEO so I can take my time and see if it stays smooth and no drop outs or anything.

[94scgt]

Uhm if i were you i would ck the o2 sensors if they are toasted or need cleaning they would make our cars run like crap just my 2 cents

[KK95GT]

Wouldn't computer codes show up if the O2s were a problem?

[KK95GT]

Thought I’d dig this thread back out and re-run it. I’ve seen this problem listed before here and in other threads, maybe worded a little differently, but essentially the same problem. Have never seen any solutions listed though….

The only thing I can think of at this point is that I need a new computer. I’ve driven the car for a couple months now and the car works fine in every way, except when I have it floored (wide open throttle). I can consistently run the car up and down to and from 5000 RPM and it will hold at 5000 RPM as long as I want with no issues at part throttle. For that reason, it just can’t be the normal wires, fuel pump, fuel flow, injectors plugs, plug gap, that type of problem. It has to be a computer or sensor signal to the computer problem. The car runs fine, as long as it’s not floored. When it’s floored it bogs and will slow down and keep slowing down as long as I keep it floored. Drop back to part throttle, and it picks right back up.

Other than replacing the TPS which tests ok or the computer which really should have no way of being able to change its own settings (both of which I hate to just throw money at and buy for the sake of change), at this point I’m still at a loss for a solution.

Anyone had this problem and an explanation as to what solved it?