I am trying to figure out what is wrong with my 98 4x4x2 blazer.

I have been having what felt like transmission problems. down shifting at 60 mph, loss of power and RPMs going up.

took to the local trans shop to get it checked (was free. had a coupon

no luck. not transmission. they pulled the following codes

158 MAP

121 TPS

300 misfire

106 MAP sensor high.


what are those codes? What could be worng. I have been trying to fix th 300 misfire for a while. think i need new injectors, but it could be somethign different with the other codes. any help would be very nice.

 

I just threw P0300 and it was my spider injector assembly @ 125,000 miles. With the other codes i would test your map sensor to see if the sensor is bad and if it is, replace it. Your TPS code might be related to your Map codes, obviously test it as well and replace as needed. As always the P0300 could also be related with the MAP sensor or TPS or anything else under your hood

 

I'd guess you have a problem with the +5V power supply from the PCM to the MAP & TPS sensors. Problems with these two items could lead to the P0300 code.