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Chris (aka-Moose)
Chris (aka-Moose), Technician
Category: Chevy
Satisfied Customers: 48626
Experience:  16 years of experience
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2002 s10 chev blazer 4.3 has 180 k miles had eng code P0420

Customer Question

2002 s10 chev blazer 4.3 has 180 k miles
had eng code P0420 first (catylist system efficiency below threshold bank 1) for 2 days it ran a little sluggish seemed to be some loss of power, especially going uphill
then erased P0240 code
then started running like crap struggles to go over 40mph on highway actually bogged down with increased acceleration
not shifting right had to pull over to get out of traffic
now has code P0756 (shift sol. B performance or stuck off) then it also got an additional P0101( MAF A circuit range performance)
don't know where to start or what to check first it starts ok , eng. seems to idle normal and revs ok at idle
Submitted: 1 year ago.
Category: Chevy
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Expert:  Chris (aka-Moose) replied 1 year ago.

Welcome, I'm Chris (aka Moose). Experts aren't employees / agents of Just Answer. We are independent service providers using the Site to sell their Expert knowledge to Customers. I strive to provide EXCELLENT 5 STAR service, let me know what's needed from me so your pleased.

Your catalyst efficiency code means the converter is starting to clog and is no longer cleaning the emissions. This can cause a power loss. The MAF sensor code can normally be resolved by just spray cleaning the MAF sensor with brake cleaner to clean it of debris effecting its reading performance. The solenoid code can mean the solenoid has failed but can also mean another issue within the transmission is occurring and the computer thinks the solenoid operation is to blame. Any noticed concerns with the transmission in any gear, up shifts or downshifts?

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Customer: replied 1 year ago.
hadn't noticed anything out of the ordinary with shifting But I don't know where to start or what to check first
Since these codes all came at once within a couple of days can one problem be causing the others? Can the convertor problem be causing the MAF sensor problem by restricting airflow? I don't know what to look at first and not sure how to check a convertor for clogging. I'm at (###) ###-####
Expert:  Chris (aka-Moose) replied 1 year ago.

Actually these are all 3 separate issues. The MAF sensor has a slim possibility of causing the converter code but its slim. Addressing the MAF code first by cleaning it then clearing the codes is what needs to be done first. The trans code is in no way related to the others but if your noticing no symptoms what so ever with the transmission then the solenoid is likely just weak and failing intermittent.

Customer: replied 1 year ago.
It's not shifting right (maybe i didn't state that correctly) but i thought the shift problem might be because of the lack of engine power when accelerating. The RPM gauge is going really higher than it normally does between shifts at higher speeds and then it bogs down and looses speed when accelerating.
Expert:  Chris (aka-Moose) replied 1 year ago.

Are all shifts at highway speed effected or just a certain shift like 3-4 for example?

Have you ever done transmission repairs?

Customer: replied 1 year ago.
About a month ago there was a very loud noise like a bang or metal impact sound when starting the eng. and it stalled. It started back up, to my surprise, and seemed to drive normally. I wonder it that could have been something in the convertor coming apart
Nothing extensive as far as experience with trans repairs other than fluid/ filter change and i replaced trans solenoids on my daughters cherokee
Customer: replied 1 year ago.
Sorry didn't answer your last question completely about shifting. It seems about normal on level grade or downhill without accelerating very much. On an incline either at higher speed or starting out from a stop it barely wants to move and really bogs down. Hasn't been any erratic shift back and forth or noticable slipping of the trans when it bogs down.
Expert:  Chris (aka-Moose) replied 1 year ago.

Thanks for this trans code I feel like the wisest choice is to get the engine running right first. Can you try cleaning the MAF sensor, clearing the codes and retesting. Is there still a converter code, if so then it needs to be replaced. Also let me know all codes that return.

Customer: replied 1 year ago.
Sorry haven't been back here for a day or two. I was WAY off as far as the apparent cause of the problem. I found a couple of hard to locate VACUUM LEAKS in some vacuum hoses and replaced the lines, not expecting much of a difference. To my surprise, it not only seems to drive and shift normally, but the 4WD, which hasn't worked this winter, started working again. The power and acceleration seem normal, all 3 engine codes DIDN'T come back, and the tachometer reads lower RPM's all the time. Catalyst system code P0420, trans. shift solenoid code P0756, and MAF sensor code P0101, all caused by leaks in some 7/32 and 5/32 vacuum line hoses.
Expert:  Chris (aka-Moose) replied 1 year ago.

Glad you got it resolved, suprised you were getting no lean codes from the O2 sensors.