K10A'sBROinSLO said:
Doubt it... they are chasing their ass.
Half the replies are practitioners of "Guess and spend auto repair". Eventually they will replace enough expensive parts and accidentally fix the problem if he listens to them. The only thing I have heard here that makes any good sense is the filters and that's just some issues with lack of regular maintenance. Thunder and bronc is the only ones I respect for a decent reply.
Yeah change the cats...guess what... if it needs cats it's because there is a pre existing problem so fix it first so you don't screw the new cat (if it actually needs one)
I about guarantee this is vacuum leaks. Mine did similar and it was Vacuum line to the Map got hard and split where it wasn't visible on the back side of the TBI. I also had cracks in all the plastic lines AND a bad gasket under the TBI.
Bet when it was running better it had a surge or a "chuggle" (term from manual).
Course if you read the factory manual the fist thing it tells you to do is look for vacuum leaks for this complaint.
I quote on diagnostics section 2-6 or the 1988 10-30 R-V-G-P lightduty service manual:
Hesitation, Sag, Stumble
In order right out of factory manual
- Perform careful visual (physical) check as described at the start of section 2 (section 2:vacuum hose leaks, Air leaks at throttle body, ignition wires, poor electrical connections IN BOLD IT SAYS The importance of this step cannot be stressed to strongly-it can lead to correcting a problem without further checks and can save valuable time)
- fuelpressur, water contamination, timing
- fuel pump
- tps
- generator output
- bad grounds (there are several up on the intake for TPS, injectors and Map
- hei
- egr
First tool to use is a decent manual. You are chasing your ass if you start anywhere else. When mine screwed up I took 10 minutes to read the diagnostic and 10 minutes later I found that bad vacuum line. $30 at the parts store later I replaced ever questionable Vacuum line on the truck. truck never ran better.
It's funny how the manual always starts with the practically free repair then works its way up to carefully testing each component to verify operation or failure before it says to replace. It start with not only the cheapest but the most common problem.
Course if you listed to half the people here you would have just spent about $800 on parts and labor. I bet you can fix it for less then $20.
