Hesistation and Popping At Low RPMs

zxtec · 04-22-2004, 06:09 AM

I need some suggestions about my 93 1.8L that is hesitating, and popping at low rpms of 1k-2k. It seems when I'm not heavy on the gas it will not hesitate as much and sometimes will disappear. When I'm heavy on the gas, I get a huge loss of power from hesitation and some popping sound near the cat.(probably destroying my cat) But after the engine revs higher then 2k, the hesitation stops.

No CEL has come on. The only mod I have is a generic cone intake filter. I have new wires and new bosch platnium spark plugs. I've read another thread that Subaru's don't like bosch plugs...has anyone had hesitation due to bosch plugs?(hard to believe it's the cause) I've cleaned and checked the IAC and PCV which seem to be good.

What should the resistance range on the coil pack be?

I'm planning on checking the o2 sensor but I'm thinking it's not the problem since a CEL didn't come on.

Anyone have some ideas on what else to check? Any info or suggestions would be greatly appreciated. Thanks in advance

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Hayes · 04-22-2004, 12:30 PM

Typical of an engine running very lean fuel mix. Dirty injectors, fuel filter, fuel pump regulater and last but not least induction air leak like a vacume hose of or intake manafold gasket or ???? EdHayes

Nicklbrso · 04-22-2004, 12:38 PM

yes it definitely sounds like a lean condition. Have you checked your plug wires? You mentioned they are new but are they frayed at all? You may want to make sure all the plug boots are completely dry from any water that may have got in there and make sure the boots are on tight. Also check the coil for any water.

zxtec · 04-22-2004, 09:53 PM

Thanks guys for the suggestions. I'll be checking on those items this weekend. The fuel filter was change about a year ago.

Wires are not frayed and the sparkplug boots are clean, dry and nice and tight.

Anyone know what the resistence range for the coil pack is?

Thanks again

Machine Age Victim · 04-22-2004, 10:10 PM

it's your front O2 sensor, you should be throwing a CEL tho

zxtec · 04-22-2004, 10:21 PM

I was thinking its the o2 but like I said I didn't get a CEL. I will be checking that this weekend also. I really wish the car would throw a CEL so I could have something to go by.

Shinji N · 05-26-2004, 01:26 PM

I had the same problem in my 2001 2.5rs exactly except instead of 2000 rpm I had to go up to 3000rpm before it would drive normal, and it would STILL not accelerate like it used to.

Swapped the O2 sensor last weekend. Car is driving like it used to.

btw, I was not getting a check engine light for the O2 sensor

04-22-2004, 06:09 AM	#1
zxtec Scooby Newbie Member#: 54322 Join Date: Feb 2004	Hesistation and Popping At Low RPMs I need some suggestions about my 93 1.8L that is hesitating, and popping at low rpms of 1k-2k. It seems when I'm not heavy on the gas it will not hesitate as much and sometimes will disappear. When I'm heavy on the gas, I get a huge loss of power from hesitation and some popping sound near the cat.(probably destroying my cat) But after the engine revs higher then 2k, the hesitation stops. No CEL has come on. The only mod I have is a generic cone intake filter. I have new wires and new bosch platnium spark plugs. I've read another thread that Subaru's don't like bosch plugs...has anyone had hesitation due to bosch plugs?(hard to believe it's the cause) I've cleaned and checked the IAC and PCV which seem to be good. What should the resistance range on the coil pack be? I'm planning on checking the o2 sensor but I'm thinking it's not the problem since a CEL didn't come on. Anyone have some ideas on what else to check? Any info or suggestions would be greatly appreciated. Thanks in advance * Registered users of the site do not see these ads.

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04-22-2004, 12:30 PM	#2
Hayes Scooby Specialist Member#: 11808 Join Date: Oct 2001 Location: Cape Coral,FL	Typical of an engine running very lean fuel mix. Dirty injectors, fuel filter, fuel pump regulater and last but not least induction air leak like a vacume hose of or intake manafold gasket or ???? EdHayes

04-22-2004, 12:38 PM	#3
Nicklbrso Scooby Specialist Member#: 44887 Join Date: Oct 2003 Chapter/Region: NESIC Location: ME Vehicle: 00 GC6 Silver	yes it definitely sounds like a lean condition. Have you checked your plug wires? You mentioned they are new but are they frayed at all? You may want to make sure all the plug boots are completely dry from any water that may have got in there and make sure the boots are on tight. Also check the coil for any water.

04-22-2004, 09:53 PM	#4
zxtec Scooby Newbie Member#: 54322 Join Date: Feb 2004	Thanks guys for the suggestions. I'll be checking on those items this weekend. The fuel filter was change about a year ago. Wires are not frayed and the sparkplug boots are clean, dry and nice and tight. Anyone know what the resistence range for the coil pack is? Thanks again

04-22-2004, 10:10 PM	#5
Machine Age Victim Scooby Specialist Member#: 29961 Join Date: Nov 2002 Chapter/Region: South East Location: my job is a hobbie to most Vehicle: 2008 BMW 328i Conv. 2001 Kawasaki ZR-7S	it's your front O2 sensor, you should be throwing a CEL tho

04-22-2004, 10:21 PM	#6
zxtec Scooby Newbie Member#: 54322 Join Date: Feb 2004	I was thinking its the o2 but like I said I didn't get a CEL. I will be checking that this weekend also. I really wish the car would throw a CEL so I could have something to go by.

05-26-2004, 01:26 PM	#7
Shinji N Scooby Specialist Member#: 3987 Join Date: Feb 2001 Location: Los Angeles, CA Vehicle: 1999 Miata Black	I had the same problem in my 2001 2.5rs exactly except instead of 2000 rpm I had to go up to 3000rpm before it would drive normal, and it would STILL not accelerate like it used to. Swapped the O2 sensor last weekend. Car is driving like it used to. btw, I was not getting a check engine light for the O2 sensor