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Category: Ford
Satisfied Customers: 26088
Experience:  ASE CERTIFIED TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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I have 99 escort zx2. The engine seems to stumble, lurch and

Customer Question

I have 99 escort zx2. The engine seems to stumble, lurch and sometimes backfire only when warm and during moderate acceleration especially after idling or stop and go traffic. Seems fine at idle, on Highway and usually during a hard accelation. What are possible causes for this issue which gets worse on warmer days.
JA: Cars do make very odd noises -- They help the mechanics figure out what's wrong. They are terrific with my old Grand Cherokee. Are you hoping to fix this yourself?
Customer: Ummm......yes
JA: Is there anything else important you think the Ford Mechanic should know about your Ford?
Customer: I do not believe the issue is plugs, wires or ignition coil as they have been replaced recently and did not make difference in these symptoms. Also compression seems ok all cylinders are between 150 and 165 psi.
JA: Our top Ford Mechanic is ready to take your case. Just pay the $5 fully refundable deposit and I'll fill the Ford Mechanic in on everything we've discussed. You can go back and forth with the Ford Mechanic until you're 100% satisfied. We guarantee it.
Submitted: 1 year ago.
Category: Ford
Expert:  AMEDEE replied 1 year ago.

Hello and welcome! My name is ***** ***** I can assist you with your question. Is the check engine on? Are there any codes in the computer? Are you looking for some possible causes or would you like me to walk you through this diagnoses?

Customer: replied 1 year ago.
there are no codes and check engine light is off. i would like to know possible causes as well as suggestions to help with the diagnosis.
Expert:  AMEDEE replied 1 year ago.

Thanks for the reply and sorry for the delay! My experience has been that this is caused by bad secondary ignition components and or a bad mass air flow sensor provided the fuel pressure is good when this happens. Just be sure that the air intake snorkle from the MAF sensor to the throttle body is not cracked or ripped in anyway and that it is securely tightened on both sides.

Customer: replied 1 year ago.
I have replaced the plugs and wires as well as the ignition coil. It made no difference in the symptoms. I have checked the intake and did not find anything wrong. What is the best way to test fuel pressure (there is no test port on the fuel rail as on some 2.0 engines)? Also the problem seems temperature related, do you have any ideas about why a fuel pressure or bad MAF sensor issue would be worse when warm?
Expert:  AMEDEE replied 1 year ago.

Hello and sorry for the delay! YES, tempature is a huge factor in resistance. And when a sensor or an electrical part starts to go bad, it will go bad only under certain conditions or certain tempatures. For example, it might stop working when it gets hot but it may start working again once it cools off. I dont believe there is a fuel pressure test port on this engine but I could be wrong. You will have to double check. If not, then you will need to use a fuel pressure gauge and adapters to tap into the fuel line to check fuel pressure.