Driveability Issue

96Blazer LS · 10-20-2009, 06:27 PM

I have a friend with a 99 Blazer 4 door 2wd. When starting off from a stop it jerks and eventually when up to speed its runs fine also the tach jumps. This is what I am told is going on I have not had a chance to look at it, the check engine light is on as well. I thought it may be fuel pressure regulator, fuel injector issue. Anyone ever had this happen to them?

s10pimpin209 · 10-20-2009, 06:53 PM

get the codes checked. thats a good start.

lee-mill · 10-20-2009, 07:05 PM

prolly a gummed up injector, id run seafoam throw it first, see if that helps

96Blazer LS · 10-20-2009, 10:29 PM

Quote: Originally Posted by s10pimpin209

get the codes checked. thats a good start.

Yeah, I am going to check the codes for him, but thought I would ask if this has happened to anyone else. There have been a number of sensors replaced from the person he purchased the truck from. Before my friend bought the truck, it was checked at the dealership. The dealer said they would have to remove the manifold and look at things, about $700-$800. He bought the truck at a reduced price with the issue and looking to get it fixed now.

96Blazer LS · 11-05-2009, 05:45 PM

The engine code shows to be a P0420 - Catalyst System Efficiency Below Threshold (Bank 1). The cat has been replaced with a aftermarket cat, but the o2 sensors are original. Could the o2 sensors be defective? Which o2 sensor is considered to be bank 1

96Blazer LS · 11-05-2009, 05:50 PM

The tach jumps erratically, is there a fix for this?

zacharyh687 · 11-06-2009, 01:13 AM

take the truck to a tranny shop i have a 2000 gmc seira and they have the same tranny and s10s the 4l60e. it would act up and when i would be driving down the road the tach would jump up and down and it would not shift right some tranny shops will check it out for little or no cost... i do not feel that a faulty o2 sensor would do that or a cat.. there is only 2 o2 sensors on that truck one pre cat and one post cat. my brother owns a blazer same year model too and that is how his o2 sensors are set up. hope this helps you

95tahoelt · 11-06-2009, 01:29 AM

there are 3- O2 sensors bank 1, bank 2 and 1 after the cat.

sounds like a ground issue to me or dist. cap..

01cherryreds10 · 11-06-2009, 01:48 AM

Does it take a while for it to start? Possibly be a bad CKP if it is doing that with the tach and runs rough from a stop. For the injectors you can push nitrogen through the spider to clean them. That's if the shop has access. Do you have access to a scan tool that will display engine data?

zacharyh687 · 11-06-2009, 02:56 PM

well it it is a misfire problem caused by the fuel injectors or somthing with the ignition system the check engine light would flash indicating a severe misfire. is the check engine light flashing??? also i know that if there is something wrong with the tranny it can have the same symptoms that he is explaining thats what my 2000 gmc seira would do and it is not an uncommon problem with the 4l60e trans it is not the best trans in the world.

96Blazer LS · 11-16-2009, 05:29 PM

I will have to ask my friend, the guy that owns the truck. I looked under to the hood and looked as if the plug wires are new and distributor cab looked to be replaced, but never know what previous owner put in with out taking it all back out and looking at it. The check engine light does not flash, just get code: 0420 Catalyst System Efficiency Below Threshold Bank 1. Just that code alone doesn't make since with the jerking. The jerking from take off from stop is worse when the weather is warm outside. I was going to suggest to do plugs, cap, wires and rotor, just to make sure the previous owner didn't put in cheap plugs, or crack a plug when installing it. Start with the basics at least to eliminate the simple stuff.

SpiderDallas · 11-16-2009, 07:08 PM

Well I looked up the code for you on identifix and it says that the cat is bad. Usually a P0420 code means a bad cat. Hope you get it fixed just figured I would help out.

Bill Wheats · 11-16-2009, 08:31 PM

Before you start replacing parts like the CAT, I would recomend running some seafoam through the gas (not in the oil) and connecting a vacuum gauge with enough vac line to make it into the dash.
Post your results....

SpiderDallas · 11-16-2009, 08:42 PM

I'm just posting up what the code means. Sorry just trying to help out.

Bill Wheats · 11-16-2009, 09:15 PM

You got it right, but you have to remember that the codes only point to a direction. You still need to use your senses and trouble shooting techniques to solve the cause.

00bluegtp · 11-16-2009, 09:25 PM

Check the cat and see if it is clogged?

Bill Wheats · 11-16-2009, 09:43 PM

Quote: Originally Posted by 00bluegtp

Check the cat and see if it is clogged?

The vacuum gauge will check it real quick, and you don't have to pull the exhuast....
Also the cat may just be getting plugged with fuel, which means once the cause is taken care of the CAT will clean up while driving....

But feel free to do what you want.

10-20-2009, 06:27 PM	#1
96Blazer LS Registered User Join Date: Nov 2008 Posts: 21 Location: User is: OffLine	Driveability Issue I have a friend with a 99 Blazer 4 door 2wd. When starting off from a stop it jerks and eventually when up to speed its runs fine also the tach jumps. This is what I am told is going on I have not had a chance to look at it, the check engine light is on as well. I thought it may be fuel pressure regulator, fuel injector issue. Anyone ever had this happen to them?
	[Reply w/Quote]

10-20-2009, 06:53 PM	#2
s10pimpin209 Knowledge is power. Age: 21 Join Date: Oct 2008 Posts: 826 Location: Stanislaus County, CA User is: OffLine	Re: Driveability Issue get the codes checked. thats a good start.
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10-20-2009, 07:05 PM	#3
lee-mill where's my chippy? Age: 20 Join Date: Jun 2007 Posts: 7,846 Location: staatsburg, ny User is: OffLine	Re: Driveability Issue prolly a gummed up injector, id run seafoam throw it first, see if that helps
	[Reply w/Quote]

10-20-2009, 10:29 PM	#4
96Blazer LS Registered User Join Date: Nov 2008 Posts: 21 Location: User is: OffLine	Re: Driveability Issue Quote: Originally Posted by s10pimpin209 get the codes checked. thats a good start. Yeah, I am going to check the codes for him, but thought I would ask if this has happened to anyone else. There have been a number of sensors replaced from the person he purchased the truck from. Before my friend bought the truck, it was checked at the dealership. The dealer said they would have to remove the manifold and look at things, about $700-$800. He bought the truck at a reduced price with the issue and looking to get it fixed now.
	[Reply w/Quote]

11-05-2009, 05:45 PM	#5
96Blazer LS Registered User Join Date: Nov 2008 Posts: 21 Location: User is: OffLine	Re: Driveability Issue The engine code shows to be a P0420 - Catalyst System Efficiency Below Threshold (Bank 1). The cat has been replaced with a aftermarket cat, but the o2 sensors are original. Could the o2 sensors be defective? Which o2 sensor is considered to be bank 1
	[Reply w/Quote]

11-05-2009, 05:50 PM	#6
96Blazer LS Registered User Join Date: Nov 2008 Posts: 21 Location: User is: OffLine	Re: Driveability Issue The tach jumps erratically, is there a fix for this?
	[Reply w/Quote]

11-06-2009, 01:13 AM	#7
zacharyh687 Registered User Age: 22 Join Date: Oct 2009 Posts: 4 Location: User is: OffLine	Re: Driveability Issue take the truck to a tranny shop i have a 2000 gmc seira and they have the same tranny and s10s the 4l60e. it would act up and when i would be driving down the road the tach would jump up and down and it would not shift right some tranny shops will check it out for little or no cost... i do not feel that a faulty o2 sensor would do that or a cat.. there is only 2 o2 sensors on that truck one pre cat and one post cat. my brother owns a blazer same year model too and that is how his o2 sensors are set up. hope this helps you
	[Reply w/Quote]

11-06-2009, 01:29 AM	#8
95tahoelt Registered User Age: 41 Join Date: Jul 2003 Posts: 399 Location: Westland, Michigan User is: OffLine	Re: Driveability Issue there are 3- O2 sensors bank 1, bank 2 and 1 after the cat. sounds like a ground issue to me or dist. cap..
	[Reply w/Quote]

11-06-2009, 01:48 AM	#9
01cherryreds10 Former S10 enthusiast Age: 19 Join Date: Jan 2007 Posts: 5,640 Location: Illinois User is: OffLine	Re: Driveability Issue Does it take a while for it to start? Possibly be a bad CKP if it is doing that with the tach and runs rough from a stop. For the injectors you can push nitrogen through the spider to clean them. That's if the shop has access. Do you have access to a scan tool that will display engine data?
	[Reply w/Quote]

11-06-2009, 02:56 PM	#10
zacharyh687 Registered User Age: 22 Join Date: Oct 2009 Posts: 4 Location: User is: OffLine	Re: Driveability Issue well it it is a misfire problem caused by the fuel injectors or somthing with the ignition system the check engine light would flash indicating a severe misfire. is the check engine light flashing??? also i know that if there is something wrong with the tranny it can have the same symptoms that he is explaining thats what my 2000 gmc seira would do and it is not an uncommon problem with the 4l60e trans it is not the best trans in the world.
	[Reply w/Quote]

11-16-2009, 05:29 PM	#11
96Blazer LS Registered User Join Date: Nov 2008 Posts: 21 Location: User is: OffLine	Re: Driveability Issue I will have to ask my friend, the guy that owns the truck. I looked under to the hood and looked as if the plug wires are new and distributor cab looked to be replaced, but never know what previous owner put in with out taking it all back out and looking at it. The check engine light does not flash, just get code: 0420 Catalyst System Efficiency Below Threshold Bank 1. Just that code alone doesn't make since with the jerking. The jerking from take off from stop is worse when the weather is warm outside. I was going to suggest to do plugs, cap, wires and rotor, just to make sure the previous owner didn't put in cheap plugs, or crack a plug when installing it. Start with the basics at least to eliminate the simple stuff. Last edited by 96Blazer LS : 11-16-2009 at 05:30 PM. Reason: wrong word
	[Reply w/Quote]

11-16-2009, 07:08 PM	#12
SpiderDallas Registered User Age: 27 Join Date: Oct 2009 Posts: 146 Location: Dallas,TX User is: OffLine	Re: Driveability Issue Well I looked up the code for you on identifix and it says that the cat is bad. Usually a P0420 code means a bad cat. Hope you get it fixed just figured I would help out.
	[Reply w/Quote]

11-16-2009, 08:31 PM	#13
Bill Wheats Registered User Join Date: Apr 2008 Posts: 1,825 Location: Maine User is: OffLine	Re: Driveability Issue Before you start replacing parts like the CAT, I would recomend running some seafoam through the gas (not in the oil) and connecting a vacuum gauge with enough vac line to make it into the dash. Post your results....
	[Reply w/Quote]

11-16-2009, 08:42 PM	#14
SpiderDallas Registered User Age: 27 Join Date: Oct 2009 Posts: 146 Location: Dallas,TX User is: OffLine	Re: Driveability Issue I'm just posting up what the code means. Sorry just trying to help out.
	[Reply w/Quote]

11-16-2009, 09:15 PM	#15
Bill Wheats Registered User Join Date: Apr 2008 Posts: 1,825 Location: Maine User is: OffLine	Re: Driveability Issue You got it right, but you have to remember that the codes only point to a direction. You still need to use your senses and trouble shooting techniques to solve the cause.
	[Reply w/Quote]

11-16-2009, 09:25 PM	#16
00bluegtp Registered User Join Date: Jul 2009 Posts: 92 Location: User is: OffLine	Re: Driveability Issue Check the cat and see if it is clogged?
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11-16-2009, 09:43 PM	#17
Bill Wheats Registered User Join Date: Apr 2008 Posts: 1,825 Location: Maine User is: OffLine	Re: Driveability Issue Quote: Originally Posted by 00bluegtp Check the cat and see if it is clogged? The vacuum gauge will check it real quick, and you don't have to pull the exhuast.... Also the cat may just be getting plugged with fuel, which means once the cause is taken care of the CAT will clean up while driving.... But feel free to do what you want.
	[Reply w/Quote]