1999 Suburban running rough for a long time

Siquewhat

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Hi!
I have a 1999 Suburban that has been running bad for a long time and has had to be towed several times.
The symptoms have varied a bit but include, stuttering when accelerating from stand still, hesitation when accelerating at lower speed (50 km/h) and also completely stalling at a red light for instance.
From the beginning it threw p0171 and p0174 almost every day, but never stopped. During a long trip it suddenly died on the higway and I was towed to work shop not specilized in Chevrolet, since they are not so common over here. They changed the MAF sensor and when I collected it it ran about an hour and then died at would not restart. After towing again to my regular work shop who is a Chevrolet guy he replaced the fuel pump (second time in about 5 years) and it ran ok the first day. Day 2 it threw P0420, P0430 and P0102 and started to run rough in a new way, the stuttering from standstill, dying at redlights, and also accelerating by it self when my foot is on the break. I cleared the codes and now only P0102 is threwn every time I drive and the last mentioned symptoms are present.

I have tested that 5 and 12 volt is present in the MAF sensor connector. I still have the old MAF which my work shop guy thinks never was defect and I am going to switch back to and see if it makes any difference,

Any ideas what I should do or try? I have reached a decision to get rid of the car since it is too unreliable, sadly since it only has 280 000 km on it and almost no rust.

Grateful for any input

/Alex
 
You had converter codes and a clogged converter can cause a P0102
 
You had converter codes and a clogged converter can cause a P0102
Thanks! Yes I am aware that P0420 and P0430 are catalyst converter related. But is it likely that us the cause since I only got those codes once and in conjuction to replacing the fuel pump (in August last year) ? P0102 is the recurring code.
 
Thanks! Yes I am aware that P0420 and P0430 are catalyst converter related. But is it likely that us the cause since I only got those codes once and in conjuction to replacing the fuel pump (in August last year) ? P0102 is the recurring code.
And if you read the link it says a clogged cat regardless of what other codes can cause a P0102. You can't get air to come in if exhaust can't go out. Check the cat.
 
And if you read the link it says a clogged cat regardless of what other codes can cause a P0102. You can't get air to come in if exhaust can't go out. Check the cat.
Thanks, I missed the bottom of the link.
 
Do you know if this is a common cause given my symptoms? Do the cat cleaner fluids work or is it a waste of time?
 
Another thing, I connected my OBD scanner and read live data and the MAF reading is constantly 0 g/s, regardless of rpm or speed, it never displays a value greater than 0. If that points in any direction?
 
Are you sure you don't have a vacuum leak. Have you tried a smoke test?
 
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