Hey,
A friend has an 87 Firebird Trans Am with the LG4 305. Runs good but has been throwing 2 codes as of late. The first is code 13(I beleive), the code for o2 sensor, so we plan on replacing the o2, but it also throws code 21 for TPS circuit. What does the TPS affect, besides the SES light, on the LG4? Any ideas? Are these two related? Thanks in advance.

Martin

 

Martin, the TPS is the throttle postion sensor. The computer uses this to help calculate how much fuel the engine needs at any moment. Might just need a new sensor.

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85 Z28 LG4 with 224,000

 

Thanks for the info, we will trouble shoot hopefully soon, but if anyone has any experience is there any things to look out for? Any simple things easily missed?

Thanks
Martin
PS 224k miles is always good to see, just shows how good the cars are if well taken care of.