97 Blazer auto 4x4 6 cyl vortec engine: The problem seems to be the lack of performance when accelerating above 55 mph. If I push gas pedel down (like to pass on highway) it will raise the rpm's but does not gain speed on demand...However, it willeventually gain steady speed if I slowly and gradually apply the gas pedel down. I am wondering if theEGR valve or the MAP sensor might have an effect on this lagging performance? Also, can anyone confirm the exact locationwhere the MAP sensor might be on this vehicle should I need to clean or replace it? Any comments or suggestions will be greatly appreciated. Thanks! skoot61

 

*Moving to 2nd Gen Tech*

When was the last time that you had a tune up done? Plugs/Wires/Cap/Rotor? Cleaning the MAF sensor (directly behind the air filter housing) and the EGR valve (don't forget the new gasket) should only help.

The 'problem' you are experiencing may be the torque converter unlocking as you press on the gas, raising the RPM, but not necessarily increasing ground speed. This is to get the engine up into a higher RPM for better performance. When you experience this, is it on light acceleration or are you putting the pedal to the floor and it lags like this? WOT (wide open throttle) should result in first the unlocking of the torque converter, followed very quickly by the downshift into 3rd at 55MPH, but a slow roll into the throttle (circumventing a kickdown to 3rd) will result in the torque converter only unlocking which may momentarily seem like the truck is trying to go faster, but isn't... I guess it depends on how long in duration it feels like it isn't doing anything and the throttle position (etc) that would affect it.

 

Thanks swatlkk for your intrest and quick reply..I can't remember havingany tune-up services for this vehicle in the recent past so I am hoping it might be just in desperate need of a tune-up.Good point swatlkk, for considering the torque converter. Itcertainly may be the root of this problem however, since I've had both the tranny and torque converter replaced within the last 12,000 miles I want to keep the thoughts of servicing the torque converter againlow on the process of elimination list till I at leastget a tune-up. To answer your question about how the Blazer was beingthrottled up.... I will need to test drive and monitor the Blazer again to be able to accurately sayexactly what happens when and how throttling is being applied to determinethe timing of downshifting and upshifting reactions. I will repost the results after another test drive. Skoot61

 

A tune up definitely sounds like a good starting point.

About the torque converter, I wasn't suggesting that it was the cause of the problem. More stating what it does during normal operation. The length of time and other factors I mentioned will determine whether it is operating normally or abnormally.

 

Yes, swartlkk I realize the torque converter was only a suggestion of a possible cause... But, it wasa good one...( one I hadn't considered) I'm not one todiscount anything out of the equation of possibilities until I can confirm all the the obvious components function properly. Asimple tune-up and servicing sensors is the least expensive and what I'm hoping for.We shall see about that...lol Anyway, my repair plan strategy is to test drive and closely monitor throttling the Blazer, do a full tune-up, compare how much better or worse it runs after that... Then,if needed Iwill re-examinethe torque converter further. I will repost results... Skoot61

 

The follow-up of lacking performance: Problem resolved with the basic Tune-Up. The engine now runs strong and is responsive to throttling up into highway traffic.I am very pleased with the results. I do recommend taking the time (about 10 mins) to relocate the steering shaft out of the way to access the #3 spark plug. I followedthe info from this linkand I'm glad I did...so much easier than trying to get around that shaft.. http://www.s10forum.com/forum/f107/h...k-plug-224471/
Replacement parts total $299.40 include:6 AC Delco Platinum plugs $45.04
AC Delco Ignition Wire kit $119.35
AC Delco Distributor Cap$34.68
AC Delco Rotor $11.17
AC Delco Air Filter $17.57
Standard Ignition Coil $60.78
EGR Gasket $1.97