[lstern6]

Hi All,
Can anybody help solve this mystery? The faster I try to give her gas, the more she chokes. If I give it to her slowly, she's fine. But at almost any speed (although more prevalent at slower speeds) when I put my foot down, she chokes on the fuel, lurching the car. When idling, she sputters about every 10 -15 seconds.

I have a '99 Cougar with a 2.5 DHOC
Thus far I have only installed/replaced:
Plugs and wires
AEM short RAM intake
Remus Exhaust
Random Tech custom CAT converter

In order to remedy this issue, I have also cleaned the MAF, run 2 consecutive tanks of Techron cleaner, and checked the timing (fine). But it would seem that none of this has helped.

Any suggestions?? Thanks in advance.

 

[TheDragon]

My first inclination is that she’s getting too much air. Or, the air she is getting is not being properly metered. Make sure your MAF is plugged in. Try cleaning it. Could be defective. Just a couple of quick thoughts.

 

[lstern6]

Well, I have cleaned it, and it is plugged in. How would I know if it is defective?
Another Cougarfile suggested that my mods were not enought to warrant a bigger MAF or bigger injectors or the like. Do you disagree?

 

[eurocrisp]

::coughcough fuel pump coughcough::

Do you know if youre return or returnless?

Did you put anything but Ford wires on the car? what plugs?

edit: Stock maf and 17lb injectors are good to 220hp.

 

[lstern6]

I changed the fuel filter about 9 months ago. I will change it again.
The plugs and wires are Ford, but I'm not sure if they are exactly the same wires.

 

[lstern6]

I'm not sure about the returnless or not... how do I find out? Also, fuel pump?? not filter??

 

[Fett]

Yea, sounds like your fuel pump is clogged....common problem on late 99+ Cougars.

 

[TheDragon]

How and with what did you clean your MAF?

Is it safe to assume that your car runs fine except when you floor it? Can you drive at 4000+ RPMs without problems?

If the answers to these questions are yes, I would still focus on the MAF. Although, not being an expert with Cougars, I wouldn’t discount what the others have suggested just yet. Too little fuel would have similar results as too much air.

When you guys say clogged fuel pump, are you talking about the pre-filter on the pump inlet being clogged? Cause if he can drive okay at higher RPMs how is the motor getting the fuel if the fuel pump is clogged? Pressure???

Is there a FPR or is the pump variable? That is to say, how is fuel pressure handled in these cars?

I seriously need to get a Cougar shop manual.

 

[eurocrisp]

if you look under your intake tract you'll see either 1 or 2 steel lines. If you have 1 you're returnless, if you have 2 you're return. The returnLESS pumps are cheaper to produce, however at the cost of prolonged reliability. If you have 1 line and your hesitation is worse at half tank and below, thats another shoe-in symptom of fuel pump failure.

If you've got 2 lines, supposedly the return pumps are a LOT less prone to death... so then id have my A/F ratios scoped out. Might be an O2 sensor... ive heard stories of them being completely dead and not throwing a cel for like 1500 miles.

edit: Dragon, on later cars i believe the pump is told what to output by the ECU. With earlier return style fuel systems the pumps running all the time... tho there IS a FPR on the inlet line :shrug: the extent of its adjustability is unknown to me

 

[lstern6]

I am told my car is returnless. I have just replaced the fuel filter with no major change.
It would seem that the faster I put my foot down, the more she chokes. At 4000+ rpms the problem is much less prevalent. The CEL of 'running lean' comes and goes. I think I will replace the fuel pump and see what that does, but I fear that wont be the solution.
The plugs and custom CAT were replaced at the same time. That is when the problem became very obvious. Could this be a lack of 'blowback' problem??

 

[TheDragon]

Originally posted by: Neil

edit: Dragon, on later cars i believe the pump is told what to output by the ECU. With earlier return style fuel systems the pumps running all the time... tho there IS a FPR on the inlet line :shrug: the extent of its adjustability is unknown to me

Thanks.

 

[zybo2004]

On my old 99 ATX this started happening, and I took it to the dealership. I'm good friends with the Manager there and he took a look and just cleaned off the battery terminals, and tightened the wires on there. He told me the wires had some corrosion or something on them, and they weren't making a good connection. I don't know other than that, but that's what was the problem in my experience, and from reading what you said, I had the same problems pretty much.

Other than that, I'd do like the others said and check the Fuel pump...mine started going bad at about 90k miles...and at 98 I blew my engine..kinda...so I just got a new cougar..haha....anyway...Good luck, and I hope you fix it soon.

Z (jason)

 

[lstern6]

I'll check that, and have ordered a new fuel pump. I'll report back after that to let y'all know how that worked.
Thanks.

 

[1mnstang]

how many miles on your car? If you have less than 70,000 I would have ford do the fuel pump. Mine only cost me 100.00 for Ford to replace it. Ford has an out of warranty program. They will pay 80% of the cost for two separate repairs. As long as you have less than 70,000 miles on your vehicle. If the cars choking after 4000 rpm it definitely sounds like the fuel pump.

Good luck

 

[lstern6]

Good thought, but I am late for that.. 80k miles. Thanks.