Hi i have a 1996 blazer with a 4.3 it starts up idles fine as soon as u put it in drive it has no power. tested cat temp was 300 good fule presure changed map sensor and distributor and still no go . can anyone help? ty

 

Is Service Engine Soon lite on? Are there any diagnostic codes?

Explain "no power" better; does it move? Blazer history?....has it been sitting unused for a long period? Have you put a timing light on it to see if timing is advancing when throttle opened?

Is the MAF connected?

We will try to help you out.

 

When it first started acting up the check engine lite was on took it to a garage the only code was for oxygen sensor he found and replaced the one that was bad and retested it the light is out and no more codes but still dont run right. the blazer starts right up when in park u can rev it up but when u put it in drive and step on the gas it has no power it will get to 15 to 20 mph but not realy quick it dosent backfire or pop just wont accelerate. we replaced the the mas air flow, the map sensor, the whole distributor,checked the cat and the fule pressure and it still has no get up and go? up to this point it was driven everyday oil and plugs changed and basic maintenance LannyL81 thank you for reply

 

Unplug the mass airflow sensor, start it up and see if it runs better and post back, the check engine light should be on for sure but if it runs better then we have some direction to take. Also, just because you replace things dont assume that they are good, in the 15 years that i have been working on cars i've come up with an estimate that 15-20% of all aftermarket over the counter parts are junk right out of the box or not testing within stock specs and it gets worse every day. Example: I once put 4 mass airflow sensors in a grand prix and finally got a good one on the 5th try, same brand but got it from a different store, i had even replaced the connector and it was driving me nuts, one lasted a week, one was bad right out of the box, changed it in the parking lot and cleared the code and it came right back, the next one lasted 2 days and the one after that lasted almost a month, all i can figure is that the first store (Advance Auto Parts) had a bad batch apparently and they insisted it was something on my car that was "Frying" them and refused to exchange it again, so they refunded my money, i was ticked, went to a different store (Oreilly) got the same part number same brand and drove it for 40k more miles before i sold it, TRUE STORY! The point I make is...."New Parts" are not always "Good Parts" Took 6 years before I ever stepped foot in Advance Auto again cuz I was so pissed!

When you say fuel pressure is good I assume you tested it? What was the pressure at? These systems are real picky about the pressure.

Also on the distributor change, make sure you have the wires plugged into the distributor correctly, the terminals on the cap are not in order front to back.

Here to help, let me know how it acts with MAF unplugged.

 

DimeBlazr, thanks for the info and i also know what u mean about bad parts right out of the box. I will defenitly look into every thing you mentioned but i work alot during the week so i wont get to try anything till the weekend (hopefully not raining) and as for the fule pressure the mechanic at the garage who replaced my o2 sensor did the test so i will have to ask him. he also did the distributor for me but he still has no clue whats wrong . I would of been doing all this myself but whit working crazy hours i thought it would of been faster for him to do it. I was wrong so i took the blazer home and will work on it myself. so once agin thanks for the info and i will get back to you in a few days.

 

have you checked the oil and filter? Metal shavings.

I had a car do that to me, spun all the bearing on the crank, ran fine but once you try to drive nothing.

New to the forums and the truck itself, but I have had that happen to me. Hope all is well and not what i said.

 

ok i had very little time this weekend but i did get a chance to unplug the Maf and it ran the same there was no change whith it in or out .