Friends: I struggled with a code 34 fault in my '87 convertible for the last year. I cleaned and eventually replaced the throttle body (48mm to 52mm). I went to 52mm because you cannot get stock ones anymore, at least that I could find. I replaced the MAF sensor twice thinking "that must be it" but probably was not. The thing that finally made my screen run black instead of that stinking orange Service Engine Soon light was the cheapest fix of all. I replaced what, I am sure, was the original relay. It is an oval, plastic unit located on the firewall behind the battery. There are two there, one for the fuel pump and the other for the MAF sensor. After switching on and off internally for 25 years, they apparently get tired. And they cost $10.00! A ten dollar item can render a $300 sensor completely useless. It took forever to figure this out because the general wisdom is that it was something else. I would have saved a lot of money and time if I had recognized the importance of this little switch at the outset. Not every MAF Code 34 is going to be thrown because of a faulty relay. For ten bucks and 15 minutes worth of time, I would always start by replacing this part before digging into throttle bodies and sensor replacements. Since I was in the neighborhood, I replaced the fuel relay that was mounted right beside it just for grins. It was obviously the same vintage and I now know that if the fuel pump starts acting up, it's not a measly $10 part causing it. Just something to addd to the discussion for everyone. There is not a lot of mention of relays and their relevance, replacement, and diagnosis in the shop or 3rd party repair manuals. And, in my opinion, it should have been number one when dealing with a near-vintage car. Change out the cheap stuff first! Dave

 

Putting a new MAF on while using the old relays can burn out the new MAF. Always replace them both, especially if they are old.

 

Remember there are two MAF relays, a power and a burn off. I did the same thing, then replaced a relay and it was fine, problem came back and replaced both relays but havent driven the car since. Also the wires were all messed up, so be sure to check those for any fraying. For the record, no one at any of the parts store had a MAF relay, I ended up checking part numbers and found another relay to tell them what I wanted in order to get the part.

 

I replace my relays in 98 and again in 05, I think. Never the MAF itself. When I get the code, I just do it. Not sure which one goes bad or if its both. Not wasting my time to find out. Its been 7 years so I'll probably be doing it again soon.

 

An 85 is a different setup, right?