map sensor 1999 blazer

[1999blazer]

1999 blazer LS 4.3L auto 4x4 2door.196,000kms
Problem: hard to tell if it is missing or hesitating upon hard off the line acceleration.

Only does it after it warms up. When cold no miss or hesitation.
No codes (memoscan U381 scanner by UFI TECH).

New ac delco plugs, new coil I think it is made by Standard bought at Bumper to Bumper (Canada) new wires by Standard $120.00 cdn.

EGR dirty but moving freely.

recent used distributor put in from 2005. The rotor is new. The cap looked ok but I am going to replace.

The map sensor had sludge on it partially pluged. I cleaned it off I am going to replace anybody think this would be cause of hesitation or miss. Why would there be sludge on it how do I correct this. It seems that the map is getting black dirty oily covering on it.??? It shows 10in/hg at idle on the memoscaner.

Changed the MAF with used one no difference. It is clean.

The memoscan shoes erratic timing at idle??? It does not seem to be idleing rough. Would a faulty Map sensor cause erratic timing.???

THe throttle position sensor seems ok.
I have new 02 sensors coming in the mail.

I do not think for sure it is fuel pump or fuel filter do not have gauge yet I can hear the fuel pump.

I am learning as I go keep in mind not mechanic.Only had vehicle a year.
Thanks for any help.

[MT-2500]

Originally Posted by 1999blazer

1999 blazer LS 4.3L auto 4x4 2door.196,000kms
Problem: hard to tell if it is missing or hesitating upon hard off the line acceleration.

Only does it after it warms up. When cold no miss or hesitation.
No codes (memoscan U381 scanner by UFI TECH).

New ac delco plugs, new coil I think it is made by Standard bought at Bumper to Bumper (Canada) new wires by Standard $120.00 cdn.

EGR dirty but moving freely.

recent used distributor put in from 2005. The rotor is new. The cap looked ok but I am going to replace.

The map sensor had sludge on it partially pluged. I cleaned it off I am going to replace anybody think this would be cause of hesitation or miss. Why would there be sludge on it how do I correct this. It seems that the map is getting black dirty oily covering on it.??? It shows 10in/hg at idle on the memoscaner.

Changed the MAF with used one no difference. It is clean.

The memoscan shoes erratic timing at idle??? It does not seem to be idleing rough. Would a faulty Map sensor cause erratic timing.???

THe throttle position sensor seems ok.
I have new 02 sensors coming in the mail.

I do not think for sure it is fuel pump or fuel filter do not have gauge yet I can hear the fuel pump.

I am learning as I go keep in mind not mechanic.Only had vehicle a year.
Thanks for any help.

The timing is not adjustable.
But the camshaft retard needs checked/reset with a good engine capable scanner if the dist was changed.

Quit throwing parts at it and do some proper testing.
I would suggest a good fuel pressure test and a good scanner check on it.
Any check engine lights or misfires?

[MT-2500]

Originally Posted by 1999blazer

1999 blazer LS 4.3L auto 4x4 2door.196,000kms
Problem: hard to tell if it is missing or hesitating upon hard off the line acceleration.

Only does it after it warms up. When cold no miss or hesitation.
No codes (memoscan U381 scanner by UFI TECH).

New ac delco plugs, new coil I think it is made by Standard bought at Bumper to Bumper (Canada) new wires by Standard $120.00 cdn.

EGR dirty but moving freely.

recent used distributor put in from 2005. The rotor is new. The cap looked ok but I am going to replace.

The map sensor had sludge on it partially pluged. I cleaned it off I am going to replace anybody think this would be cause of hesitation or miss. Why would there be sludge on it how do I correct this. It seems that the map is getting black dirty oily covering on it.??? It shows 10in/hg at idle on the memoscaner.

Changed the MAF with used one no difference. It is clean.

The memoscan shoes erratic timing at idle??? It does not seem to be idleing rough. Would a faulty Map sensor cause erratic timing.???

THe throttle position sensor seems ok.
I have new 02 sensors coming in the mail.

I do not think for sure it is fuel pump or fuel filter do not have gauge yet I can hear the fuel pump.

I am learning as I go keep in mind not mechanic.Only had vehicle a year.
Thanks for any help.

The timing is not adjustable.
But the camshaft retard needs checked/reset with a good engine capable scanner if the dist was changed.

Quit throwing parts at it and do some proper testing.
I would suggest a good fuel pressure test and a good scanner check on it.
Any check engine lights or misfires?
Check for past present or history codes and read out misfires.