I was just getting into the foothills of colorado when my truck died on me going up a steep hill. I had the pedal to the floor but my rpms were stuck between 2000-3000 and then it died. I finally got it started i think after hitting my TPS but it still acts strange and the rpms get stuck sometimes, i basically cant go past 3000 rpms or i have problems so WOT is what is causing the problems. I am getting code #22-TPS, #34-MAP sensor voltage to low, #42-bypass or electronic spark timming circuit. So I am wondering if the TPS can cause the other codes to be throw because its acting like the TPS is bad. I did replace it last year but it was an ebay TPS so who knows. I am beginning to get use to there always being something wrong with the truck

 

I would check both the ignition control module and the distributor. I bet the pickup coil on the distributor is bad. My neighbor's 92 Blazer had the same problem with the Code 42 and it was the pickup coil on the distributor.

 

I would also check the grounds nearby. Specifically the ground to the motor to make sure all is well. Your TPS and MAP sensor could be seeing crappy voltage from a poor ground, leading to some funky issues.

 

Just an update, Tapping the TPS when it doesn't wan't to start doesn't do anything, it's hitting the MAP sensor is what gets the truck to start. I will check my grounds today but i guess my question now is can the MAP sensor cause my truck to throw a TPS and #42 code?

 

The MAP & TPS use the same +5V reference from the PCM to power the sensors. If there was a problem with MAP sensor, it could cause the power to drop to the TPS, setting a code there.

 

+1, Sounds like you found the culprit

 

Good to hear the MAP can throw the TPS off since i just replaced the TPS last year yet it's throwing the code for it. I believe i have a MAP sensor off a 88 or 89 blazer, will it work with the vortec engine even though its off a TB injected blazer?

 

I'm not sure.

RockAuto lists the TBI and MFI motors as different sensors. AC Delco has two different part numbers:

213187
Vin W MFI
$81.89

2133205
Vin Z TBI
$53.79



AutoZone only yields one part number for both motors.

Duralast SU105
$51.99



Pepboys lists separate part numbers:

EC1633
Vin W MFI
$35.99 Not In Stock

EC1602
Vin Z TBI
$35.99

 

I'm really beginning to despise AC Delco and GM. There's no freaking reason for so many versions of the same part.

Unlike the AC Compressors where {I know for a fact} the car mfrs called for different configs from Delphi for the same A6 compressor due to engine brackets, there is no reason for the electrically identical part to have so many versions. You COULD blame whoever designs the intake but let's get real.
If you dont believe me look at starter solenoids.

 

Well here is what I am wondering, the autozone version #SU105 doesn't have a gasket on the part that seals into the plenum while the advanced auto and orilies versions do have the gasket. I also found this eBay - New & used electronics, cars, apparel, collectibles, sporting goods & more at low prices
That doesn't have a gasket but is the exact same as the autozone version so can I just take the seal off my old MAP sensor?